Initial revision

[splint.git] / src / usymtab.c

/*
** LCLint - annotation-assisted static program checker
** Copyright (C) 1994-2000 University of Virginia,
**         Massachusetts Institute of Technology
**
** This program is free software; you can redistribute it and/or modify it
** under the terms of the GNU General Public License as published by the
** Free Software Foundation; either version 2 of the License, or (at your
** option) any later version.
** 
** This program is distributed in the hope that it will be useful, but
** WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
** General Public License for more details.
** 
** The GNU General Public License is available from http://www.gnu.org/ or
** the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
** MA 02111-1307, USA.
**
** For information on lclint: lclint-request@cs.virginia.edu
** To report a bug: lclint-bug@cs.virginia.edu
** For more information: http://lclint.cs.virginia.edu
*/
/*
** usymtab
**
** Lexically scoped symbol table.
**
** Unlike a normal symbol table, this table splits to reflect branches.
**
** This is necessary since symbol table entries also reflect
** some state information, like initialization, that may be
** different on different branches.
**
** For each control structure we split:
**
** { }                - a normal scope (no control) US_NORMAL
**
** if <pred> { }      - US_TBRANCH true branch
** while <pred> { }     US_FBRANCH else branch
**
** switch <pred> { }  - US_SWITCH
**
** case x:            - case scope US_CBRANCH
**                      Should be kept in a separate table, because of
**                      weird C syntax.
*/

# include "lclintMacros.nf"
# include "basic.h"
# include "structNames.h"
# include "exprChecks.h"
# include "aliasChecks.h"

/*
** Keep track of type definitions inside a function.
*/

static uentryList functypes = uentryList_undefined;

static bool dbgfree = FALSE;
static bool dbgload = TRUE;

/*@access ekind usymId@*/

/*
** Hack to prevent shadow errors from appearing when function parameters
** are entered into a new scope.
*/

static bool noshadowerror = FALSE;

/*
** Constraint: static variables can live in 1 or > 2. 
**
** except for tags.  All tags must be at the global level.
** Static tags are handled in a kludgey way.
*/

/*
** utab    is the universal symbol table
** globtab is the global environment of utab
** oldtab  is needed for conversions in dumping (after sorting the table)
**
** there can be only one usymtab!
*/

static /*@checkedstrict@*/ /*@owned@*/ /*@notnull@*/ usymtab utab;

/* Reachable environments from from utab */
static /*@checkedstrict@*/ /*@notnull@*/ /*@dependent@*/ usymtab globtab;
static /*@checkedstrict@*/ /*@dependent@*/ usymtab filetab;

/* Used for sorting for dumpage. */
static /*@checkedstrict@*/ /*@owned@*/ usymtab oldtab;

static int usymtab_lexicalLevel (void) /*@globals utab@*/ ;
static bool usymtab_isProbableNullAltBranch (sRef p_s) /*@globals utab@*/ ;
static void refTable_free (/*@only@*/ /*@null@*/ refTable p_x, int p_nentries);
static ctype usymtab_suFieldsType (uentryList p_f, bool p_isStruct) /*@globals globtab@*/ ;

static void
usymtab_freeLevel (/*@notnull@*/ /*@only@*/ usymtab p_u)
  /*@globals globtab, utab, filetab@*/ /*@modifies p_u@*/ ;

static bool usymtab_isProbableNullAux (sRef p_s) /*@globals utab@*/ ;
static /*@only@*/ cstring usymtab_unparseStackTab (usymtab p_t);
static /*@exposed@*/ /*@dependent@*/ uentry 
  usymtab_getRefTab (/*@notnull@*/ usymtab p_u, int p_level, usymId p_index);
static /*@unused@*/ /*@only@*/ cstring 
  usymtab_unparseLocalAux (/*@notnull@*/ usymtab p_s);
static /*@unused@*/ /*@only@*/ cstring 
  usymtab_unparseLocalList (/*@notnull@*/ usymtab p_s);
static /*@only@*/ cstring usymtab_typeName (/*@notnull@*/ usymtab p_t);
static void usymtab_handleParams (void)
   /*@globals utab, globtab, filetab@*/ 
   /*@modifies utab@*/ ;

static /*@exposed@*/ /*@dependent@*/ uentry 
  usymtab_addRefEntry (/*@notnull@*/ usymtab p_s, cstring p_k);
static /*@exposed@*/ /*@dependent@*/ usymtab
  usymtab_dropEnv (/*@notnull@*/ usymtab p_s);
static /*@exposed@*/ /*@dependent@*/ uentry 
  usymtab_getRefNoisy (/*@notnull@*/ usymtab p_s, int p_level, usymId p_index);

static /*@exposed@*/ /*@dependent@*/ uentry 
  usymtab_lookupQuiet (usymtab p_s, cstring p_k);
static void usymtab_printAllAux (usymtab p_s) /*@modifies g_msgstream@*/ ;
static int usymtab_getIndex (/*@notnull@*/ usymtab p_s, cstring p_k);
static /*@exposed@*/ uentry usymtab_fetchIndex (/*@notnull@*/ usymtab p_s, int p_i);
static /*@exposed@*/ uentry 
  usymtab_lookupAux (usymtab p_s, cstring p_k);
static /*@exposed@*/ /*@dependent@*/ /*@notnull@*/ usymtab 
  usymtab_getFileTab (void) /*@globals filetab@*/ ;
static int refTable_lookup (/*@notnull@*/ usymtab p_ut, int p_level, int p_index);
static bool usymtab_mustBreak (usymtab p_s);
static bool usymtab_mustEscape (usymtab p_s);

static void recordFunctionType (uentry ue)
{
    llassert (uentry_isDatatype (ue) || uentry_isAnyTag (ue)
            || uentry_isEnumConstant (ue));

  /*@-temptrans@*/
  functypes = uentryList_add (functypes, ue);
  /*@=temptrans@*/
}

static void clearFunctionTypes (void)
  /*@modifies globtab@*/
{
  uentryList_elements (functypes, el)
    {
      if (cstring_isDefined (uentry_rawName (el)))
        {
          if (globtab->htable != NULL)
            {
              hashTable_remove (globtab->htable, uentry_rawName (el));
            }

          uentry_setName (el, cstring_undefined);
        }

      /*@access uentry@*/ 
      llassert (uentry_isValid (el));
      el->sref = sRef_undefined;
      /*@noaccess uentry@*/
    } end_uentryList_elements ;

  uentryList_clear (functypes);
}

static /*@falsenull@*/ bool usymtab_isBranch (usymtab u)
{
  return (usymtab_isDefined (u) && 
          (u->kind == US_TBRANCH || u->kind == US_FBRANCH
           || u->kind == US_CBRANCH || u->kind == US_SWITCH));
}

static bool usymtab_mustBreak (usymtab s)
{
  llassert (s != GLOBAL_ENV);
  return (s->mustBreak);
}

static bool usymtab_mustEscape (usymtab s)
{
  llassert (s != GLOBAL_ENV);
  return (exitkind_mustEscape (s->exitCode));
}

void usymtab_setMustBreak () 
  /*@modifies utab@*/
{
  llassert (utab != GLOBAL_ENV);
  utab->mustBreak = TRUE;
}

void usymtab_setExitCode (exitkind ex) 
   /*@modifies utab@*/
{
  llassert (utab != GLOBAL_ENV);

  utab->exitCode = ex;
  
  if (exitkind_mustEscape (ex))
    {
      utab->mustBreak = TRUE;
    }
}

bool usymtab_isAltProbablyDeepNull (sRef s)
{
  return (sRef_deepPred (usymtab_isProbableNullAltBranch, s));
}

static bool usymtab_isProbableNullAltBranch (sRef s) 
   /*@globals utab@*/
{
  guardSet t;
  bool res;

  t = utab->guards;

  llassert (utab->env != NULL);

  /*@-mods@*/ /* These modifications are cancelled. */
  utab->guards = utab->env->guards;
  utab->env->guards = t;
  /*@=mods@*/

  llassert (usymtab_isDefined (utab));
  res = usymtab_isProbableNull (s);

  /*
  ** This reports a spurious error.  It is okay, because of
  ** the nesting relationship of usymtab environments.
  */

  /*@-mods@*/ /* Cancelling modifications. */
  /*@i1@*/ utab->env->guards = utab->guards;
  /*@i1@*/ utab->guards = t;
  /*@=mods@*/ 

  return res;
}

static /*@notnull@*/ /*@special@*/ usymtab
  usymtab_create (uskind kind, /*@keep@*/ usymtab env, bool nextlevel)
  /*@defines result@*/
  /*@post:isnull result->htable, result->guards, result->aliases@*/
{
  usymtab t = (usymtab) dmalloc (sizeof (*t));
  
  t->nentries = 0;
  t->nspace = CBASESIZE;
  t->entries = (uentry *) dmalloc (sizeof (*t->entries) * CBASESIZE);
  t->reftable = (nextlevel 
                 ? NULL
                 : (refentry *) dmalloc (sizeof (*t->reftable) * CBASESIZE));
  
  t->kind = kind;
  t->lexlevel = (env == GLOBAL_ENV ? 0 : env->lexlevel) + (nextlevel ? 1 : 0); 

  t->env = env;
  t->htable = NULL;

  t->guards = guardSet_undefined;
  t->aliases = aliasTable_undefined;

    t->mustBreak = FALSE;
  t->exitCode = XK_NEVERESCAPE;

  return t;
}

/*
** constructors
*/

static /*@only@*/ /*@notnull@*/ usymtab
  usymtab_createRoot (void) /*@modifies nothing@*/
{
  usymtab u = (usymtab) dmalloc (sizeof (*u));
  
  u->nentries = 0;
  u->nspace = CGLOBBASESIZE;
  u->entries = (uentry *) dmalloc (sizeof (*u->entries) * CGLOBBASESIZE);
  u->env = GLOBAL_ENV;
  u->lexlevel = 0;
  u->htable = hashTable_create (CGLOBHASHSIZE);
  u->reftable = NULL;

  u->guards = guardSet_new ();
  u->aliases = aliasTable_new ();

  u->mustBreak = FALSE;
  u->exitCode = XK_NEVERESCAPE;
  u->kind = US_NORMAL;

  return (u);
}

void
usymtab_initMod (void)
   /*@globals undef utab, undef oldtab, undef globtab, undef filetab @*/
   /*@modifies utab, globtab, filetab, oldtab @*/
{
  utab = usymtab_createRoot ();
  globtab = utab;
  filetab = usymtab_undefined;
  oldtab = usymtab_undefined;
}

/*
** utab should be empty?  (requires?)
**
** Adds bool types to symbol table (these are built in for now)
** Only do this is there is no library!
*/

void
usymtab_initBool ()
{
  if (context_getFlag (FLG_NOLIB))
    {
      ctype boolt = ctype_bool;

      if (context_getFlag (FLG_ABSTRACTBOOL))
        {
          uentry boolentry = uentry_makeBoolDatatype (YES);
          
          usymtab_supGlobalEntry (boolentry);
          context_addBoolAccess ();
        }
      else
        {
          uentry boolentry = uentry_makeBoolDatatype (NO);
          
          usymtab_supGlobalEntry (boolentry);
        }
      
      /*
      ** We supply values 0 and 1 for the constants, so things like
      ** while (TRUE) can be interpreted correctly.
      */

      usymtab_supGlobalEntry 
        (uentry_makeConstantAux (context_getFalseName (), boolt, 
                                 fileloc_getBuiltin (), FALSE,
                                 multiVal_makeInt (0)));
      usymtab_supGlobalEntry 
        (uentry_makeConstantAux (context_getTrueName (), boolt, 
                                 fileloc_getBuiltin (), FALSE,
                                 multiVal_makeInt (1)));
    }
}

/*
** mutators 
*/

static void
usymtab_grow (/*@notnull@*/ usymtab s)
{
  int i;
  o_uentry *oldsyms = s->entries;

  s->nspace = CBASESIZE;
  s->entries = (uentry *) dmalloc (sizeof (*s->entries) 
                                   * (s->nentries + s->nspace));

  for (i = 0; i < s->nentries; i++)
    {
      s->entries[i] = oldsyms[i];
    }

  sfree (oldsyms);

  if (s->reftable != NULL)
    {
      refTable oldRefs = s->reftable;

      s->reftable = (refentry *) dmalloc (sizeof (*s->reftable)
                                          * (s->nentries + CBASESIZE + 1));
      
      for (i = 0; i < s->nentries; i++)
        {
          s->reftable[i] = oldRefs[i];
        }

      /*@-compdestroy@*/ 
      sfree (oldRefs);
      /*@=compdestroy@*/ 
    }
      
}

static void
usymtab_addEntryQuiet (/*@notnull@*/ usymtab s, /*@keep@*/ uentry e)
{
  if (!(s->lexlevel > fileScope || !sRef_modInFunction ()))
    {
      if (uentry_isDatatype (e) 
          || uentry_isFunction (e)
          || uentry_isAnyTag (e)
          || uentry_isEnumConstant (e)
          || context_inMacro ())
        {
          /* 
          ** Not a bug.  Code like,
          **    int f (void) { typedef int tint; ... }
          ** is legal.
          */
          
          /* was nothing here! */
          /*@i@*/ e->sref = sRef_saveCopy (e->sref);
        }
      else
        {
          llparseerror 
            (cstring_makeLiteral ("Declaration outside function scope"));

          llcontbug (message ("usymtab_addEntryQuiet: inconsistent state "
                              "(lexlevel = %d, modFunction = %s) adding: %q", 
                              s->lexlevel, bool_unparse (sRef_modInFunction ()), 
                              uentry_unparse (e)));
          sRef_setGlobalScope ();
          /* make sure the sRef is not bashed! */
          /*@i@*/ e->sref = sRef_saveCopy (e->sref);
        }
    }

  if (s->nspace <= 0)
    {
      usymtab_grow (s);
    }
  
  s->nspace--;
  s->entries[s->nentries] = e;

# ifdef DOANNOTS
  if (s == globtab || s == filetab)
    {
      if (!fileloc_isLib (g_currentloc))
        {
          uentry_tallyAnnots (e, AN_UNKNOWN);
        }
    }
# endif

  if (s->htable != NULL)
    {
      hashTable_insert (s->htable, uentry_rawName (e), s->nentries);
    }

  s->nentries++;
}

static /*@observer@*/ uentry /*@alt void@*/
usymtab_addEntryBase (/*@notnull@*/ usymtab s, /*@only@*/ uentry e)
{
  /* 
  ** In theory, we shouldn't need this test because it this is
  ** only called when a library is being read, and it shouldn't
  ** ever have a duplicate entry.  In practice, its safer to
  ** leave it in, though.
  */

  uentry old;

  if (uentry_isValid (old = usymtab_lookupQuiet (s, uentry_rawName (e))))
    {
      DPRINTF (("Duplicate entry: %s", uentry_unparse (e)));
      uentry_free (e); /* duplicate */
      return old;
    }
  else
    {
      int thisentry = s->nentries;  
      
      if (uentry_isVar (e))
        {
          uentry_setSref (e, sRef_makeCvar (globScope, thisentry, 
                                            uentry_getType (e)));
        }
      
      usymtab_addEntryQuiet (s, e);
      return e;
    }
}

static usymId
usymtab_addEntryAux (/*@notnull@*/ usymtab st, /*@keep@*/ uentry e, bool isSref)
     /*@globals globtab@*/
     /*@modifies st, e@*/
{
  usymId thisentry = st->nentries;

  llassert (!uentry_isElipsisMarker (e));

  /*
  ** not true for tags
  **  llassert (usymtab_lookupSafe (uentry_rawName (e)) == uentry_undefined);
  **/

  llassertprint (uentry_isAnyTag (e) ? st == globtab : TRUE, 
                 ("non-global tag: %s / %d", uentry_unparseFull (e), st->lexlevel));

  if (st->lexlevel == fileScope 
      && (!(uentry_isStatic (e)) || uentry_isAnyTag (e))) 
    {
      st = globtab;
    }

  if (isSref)
    {
      ctype ct = uentry_getType (e);

      if (uentry_isFunction (e) && ctype_isFunction (ct))
        {
          ct = ctype_returnValue (ct);
        }

      if (uentry_isStatic (e))
        {
          sRef sr = sRef_makeCvar (st->lexlevel, thisentry, ct);

          if (sRef_isStack (sr) || sRef_isLocalState (sr))
            {
              sRef_setAliasKind (sr, AK_STATIC, uentry_whereLast (e));
              sRef_setDefined (sr, uentry_whereLast (e));
            }
          
          uentry_setSref (e, sr);
        }
      else
        {
          uentry_setSref (e, sRef_makeCvar (st->lexlevel, thisentry, ct));
        }

          }

  if (uentry_isDatatype (e))
    {
      
      uentry_setDatatype (e, thisentry);
    }

  if (uentry_isFunction (e))
    {
      ctype ct = uentry_getType (e);

      if (ctype_isFunction (ct)
          && uentryList_isMissingParams (ctype_argsFunction (ct)))
        {
          if (uentry_isDeclared (e))
            {
              voptgenerror 
                (FLG_NOPARAMS,
                 message ("Function %q declared without parameter list",
                          uentry_getName (e)),
                 uentry_whereDeclared (e));
            }
          else
            {
              voptgenerror
                (FLG_NOPARAMS,
                 message ("Function %q specified without parameter list",
                          uentry_getName (e)),
                 uentry_whereSpecified (e));
            }
        }
    }

  if (st == globtab && !uentry_isSpecified (e))
    {
      exprChecks_checkExport (e);
    }
  
  
  uentry_checkName (e);
  
  usymtab_addEntryQuiet (st, e);
  return (thisentry);
}

usymId
usymtab_addEntry (uentry e) 
   /*@globals utab, globtab@*/
   /*@modifies utab, e@*/
{
  
  llassertprint (!usymtab_exists (uentry_rawName (e)),
                 ("Entry already exists: %s", uentry_unparse (e)));

  return usymtab_addEntryAux (utab, e, FALSE);
}

void
usymtab_addGlobalEntry (uentry e)
   /*@modifies globtab, e@*/ 
{
  DPRINTF (("Add global: %s / %s", uentry_unparse (e), bool_unparse (uentry_isForward (e))));

  (void) usymtab_addEntryAux (globtab, e, FALSE);
}

/*
** supercede and replace entry use elements of entries array, and
** assign an element to a new value, and then free the old value.
** Need -deparrays to avoid errors for this. 
*/

/*@-deparrays@*/ 

static usymId
usymtab_supEntryAux (/*@notnull@*/ usymtab st, 
                     /*@only@*/ uentry e, bool isSref)
   /*@globals globtab, filetab@*/
   /*@modifies st, globtab, e@*/
{
  cstring ename = uentry_rawName (e);
  bool staticEntry = FALSE;
  int eindex;

  DPRINTF (("Sup entry aux: %s", uentry_unparseFull (e)));

  /* static tags in global scope */
  if (st->lexlevel == fileScope 
      && (!(uentry_isStatic (e)) || uentry_isAnyTag (e))) 
    {
      eindex = usymtab_getIndex (st, ename);

      if (eindex != NOT_FOUND)
        {
          uentry ce = st->entries[eindex];      
          
          if (optgenerror
              (FLG_SHADOW,
               message ("%s %q shadows static declaration",
                        ekind_capName (uentry_getKind (e)),
                        uentry_getName (e)),
               uentry_whereDeclared (e)))
            {
              uentry_showWhereLast (ce);
            }

          if (eindex == st->nentries - 1)
            {
             ;
            }
          else
            {
              st->entries[eindex] = st->entries[st->nentries - 1];
            }

          if (st->htable != NULL)
            {
              hashTable_replaceKey (st->htable, uentry_rawName (ce), 
                                    uentry_rawName (e));
            }

          uentry_free (ce);
          st->nentries--;
        }
      
      st = globtab;
    }

  if (uentry_isStatic (e)) {
    if (uentry_isFunction (e)) {
      /* Static function declarations are at the file level, even if they are in a deeped scope. */
      st = usymtab_getFileTab ();
      staticEntry = TRUE;
    } else {
      if (!uentry_isAnyTag (e) && st == globtab) 
        {
          st = usymtab_getFileTab ();
          staticEntry = TRUE;
          DPRINTF (("Static entry!"));
        }
    }
  }

  DPRINTF (("Using symtab: %s", usymtab_unparseLocalAux (st)));

  eindex = usymtab_getIndex (st, ename);
      
  if (eindex != NOT_FOUND)
    {
      uentry ce = st->entries[eindex];

      DPRINTF (("Found entry: %s", uentry_unparse (ce)));

      if (uentry_isPriv (ce)
          /* || (fileloc_isImport (uentry_whereSpecified (ce))) */
          || (uentry_isStatic (ce) 
              && uentry_isAnyTag (ce)
              && (uentry_isDeclared (ce) 
                  && !fileloc_sameFile (uentry_whereDefined (ce),
                                        uentry_whereDefined (e)))))
        {
          /*
          ** overload entry 
          **    if overloading import should do some checks!
          */

          llassert ((st->lexlevel > fileScope || !sRef_modInFunction ()));
          
          st->entries[eindex] = e;

          if (uentry_isDatatype (e))
            {
              uentry_setDatatype (e, eindex);
            }
          
          if (st == globtab && !uentry_isSpecified (e))
            {
              exprChecks_checkExport (e);
            }

          if (st->htable != NULL)
            {
              hashTable_replaceKey (st->htable, uentry_rawName (ce), 
                                    uentry_rawName (e));
            }

          uentry_free (ce);
          ce = e; 
        }
      else if (uentry_isSpecified (ce))
        {
          if (uentry_isSpecified (e))
            {
              if (fileloc_isImport (uentry_whereSpecified (ce)))
                {
                  
                  if (st->htable != NULL)
                    {
                      hashTable_replaceKey (st->htable, 
                                            uentry_rawName (ce), 
                                            uentry_rawName (e));
                    }
                  
                  uentry_free (ce); 
                  st->entries[eindex] = e;
                  ce = e;

                  if (uentry_isDatatype (e)) uentry_setDatatype (e, eindex);
                }
              else 
                {
                  if (fileloc_isImport (uentry_whereSpecified (e)))
                    {
                      uentry_free (e);
                    }
                  else
                    {
                      /* respecification errors already reported */
  
                      if (uentry_isDatatype (e)) 
                        {
                          uentry_setDatatype (e, eindex);
                        }
                      
                      if (st->htable != NULL)
                        {
                          hashTable_replaceKey (st->htable, 
                                                uentry_rawName (ce), 
                                                uentry_rawName (e));
                        }
                      
                      llassert ((st->lexlevel > fileScope || !sRef_modInFunction ()));
                      uentry_free (ce);
                      st->entries[eindex] = e;
                      ce = e;
                    } 
                }
            }
          else /* e not specified */
            {
              if (uentry_isDeclared (ce))
                {
                  llassert ((st->lexlevel > fileScope || !sRef_modInFunction ()));
                  uentry_mergeDefinition (ce, e);
                }
              else 
                {
                  llassert ((st->lexlevel > fileScope || !sRef_modInFunction ()));
                  uentry_mergeEntries (ce, e);
                }
            }
        }
      else /* ce not specified */
        {
          if (!(st->lexlevel > fileScope || !sRef_modInFunction ()))
            {
              if (uentry_isDatatype (e) || uentry_isAnyTag (e)
                  || uentry_isEnumConstant (e))
                {
                  ; /* 
                     ** Not a bug.  Code like,
                     **    int f (void) { typedef int tint; ... }
                     ** is legal.
                     */
                }
              else
                {
                  llcontbug (message ("usymtab_supEntryAux: inconsistent state "
                                      "(lexlevel = %d, modFunction = %s) adding: %q", 
                                      st->lexlevel, bool_unparse (sRef_modInFunction ()), 
                                      uentry_unparse (e)));

                  if (sRef_modInFunction ())
                    {
                      /* make sure the sRef is not bashed! */
                      /*@i@*/ e->sref = sRef_saveCopy (e->sref);
                    }
                }
            }
          
          uentry_mergeDefinition (ce, e);
        }
      
      if (isSref)
        {
          ctype ct = uentry_getType (ce);
          
          if (uentry_isFunction (ce) && ctype_isFunction (ct))
            {
              ct = ctype_returnValue (ct);
            }
          
          uentry_setSref (ce, sRef_makeCvar (st->lexlevel, eindex, ct));
                }
    }
  else /* no previous entry */
    {
      uentry outer;

      if (st->lexlevel == globScope 
          && !uentry_isStatic (e)
          && !uentry_isExtern (e)
          && usymtab_isDefined (filetab))
        {
          /*
          ** check if there is a static entry:  (i.e.,
          **   
          **    static int f ();
          **    ...
          **    int f (); 
          */
          
          eindex = usymtab_getIndex (filetab, ename);
          
          if (eindex != NOT_FOUND)
            {
              uentry ce = filetab->entries[eindex];

              uentry_setStatic (e);
              uentry_mergeDefinition (ce, e);
              staticEntry = TRUE;
              goto exitPoint;
            }
        }
      
      outer = usymtab_lookupQuiet (st->env, ename);

      /*
      ** no previous definition, add the new one
      */
      
      if (!noshadowerror 
          && uentry_isValid (outer)
          && !(uentry_isYield (e) || uentry_isYield (outer))
          && fileloc_isDefined (uentry_whereLast (e))
          && fileloc_isDefined (uentry_whereLast (outer)))
        {
          if (!uentry_sameKind (outer, e))
            {
              ; /* no error */
            }
          else
            {
              if (ctype_isUnknown (uentry_getType (outer))
                  || uentry_isForward (outer))
                {
                  ;
                }
              else
                {
                  if (optgenerror 
                      (FLG_SHADOW,
                       message ("%s %q shadows outer declaration",
                                ekind_capName (uentry_getKind (e)),
                                uentry_getName (e)),
                       uentry_whereLast (e)))
                    {
                      uentry_showWhereLast (outer);
                    }
                }
            }
        }
      
      if (st == globtab && context_getFlag (FLG_NEWDECL))
        {
          voptgenerror 
            (FLG_NEWDECL,
             message ("New declaration: %q", uentry_getName (e)),
             uentry_whereLast (e));
        }

      eindex = usymtab_addEntryAux (st, e, isSref);
    }

 exitPoint:
    return (staticEntry ? USYMIDINVALID : eindex);
}

# ifndef NOLCL
static void
usymtab_replaceEntryAux (/*@notnull@*/ usymtab st, /*@only@*/ uentry e)
   /*@globals globtab@*/ /*@modifies st, e@*/
{
  cstring ename = uentry_rawName (e);
  int eindex;

  /* static tags in global scope */
  eindex = usymtab_getIndex (st, ename);
  
  if (eindex != NOT_FOUND)
    {
      uentry ce = st->entries[eindex];      
      
      if (st->htable != NULL)
        {
          hashTable_replaceKey (st->htable, uentry_rawName (ce), uentry_rawName (e));
        }

      uentry_free (ce);
      st->entries[eindex] = e;
    }
  else
    {
      eindex = usymtab_addEntryAux (st, e, FALSE);
    }
}
# endif

/*@=deparrays@*/ 

void usymtab_supEntry (uentry e)
   /*@globals utab, filetab, globtab@*/
   /*@modifies utab, globtab, e@*/
{
    (void) usymtab_supEntryAux (utab, e, FALSE);
}

/*
** this should be lots more efficient!
*/

static /*@exposed@*/ uentry 
  usymtab_supEntryReturnAux (/*@notnull@*/ usymtab tab, 
                             /*@only@*/ uentry e, bool isref)
  /*@globals globtab, filetab@*/
  /*@modifies tab, globtab, e@*/
{
  cstring rawName = cstring_copy (uentry_rawName (e));
  bool stat = (tab == globtab) && uentry_isStatic (e);
  uentry ret;

    
  (void) usymtab_supEntryAux (tab, e, isref);

  if (stat)
    {
      ret = usymtab_lookupAux (filetab, rawName);
    }
  else
    {
      ret = usymtab_lookupAux (tab, rawName);

      if (uentry_isInvalid (ret) && usymtab_isDefined (filetab))
        {
          ret = usymtab_lookupAux (filetab, rawName);
        }
    }
  
  cstring_free (rawName);
  return ret;
}

/*@dependent@*/ /*@exposed@*/ uentry 
  usymtab_supEntryReturn (/*@only@*/ uentry e)
  /*@globals utab, filetab, globtab@*/
  /*@modifies utab, globtab, e@*/
{
  return (usymtab_supEntryReturnAux (utab, e, FALSE));
}

/*@dependent@*/ /*@exposed@*/ uentry 
  usymtab_supEntrySrefReturn (/*@only@*/ uentry e)
  /*@globals utab, globtab, filetab@*/
  /*@modifies utab, globtab, e@*/
{
  return (usymtab_supEntryReturnAux (utab, e, TRUE));
}

/*@dependent@*/ /*@exposed@*/ uentry 
  usymtab_supGlobalEntryReturn (uentry e)
  /*@globals globtab, filetab@*/
  /*@modifies globtab, e@*/
{
  uentry ret;

  ret = usymtab_supEntryReturnAux (globtab, e, FALSE);

  if (sRef_modInFunction ())
    {
      recordFunctionType (ret);
    }

  return (ret);
}

ctype
usymtab_supTypeEntry (/*@only@*/ uentry e)
  /*@globals globtab, filetab@*/
  /*@modifies globtab, e@*/
{
  usymId uid;
  ctype ret;

  if (uentry_isAbstractDatatype (e))
    {
      uid = usymtab_supAbstractTypeEntry (e, FALSE);
      ret = ctype_createAbstract (uid);
    }
  else
    {
      uid = usymtab_supEntryAux (globtab, e, FALSE);
      ret = ctype_createUser (uid);
    }

  if (sRef_modInFunction ())
    {
      recordFunctionType (globtab->entries[uid]);
    }

  return ret;
}

uentry
usymtab_supReturnTypeEntry (/*@only@*/ uentry e)
  /*@globals globtab, filetab@*/
  /*@modifies globtab@*/
{
  usymId uid;

  if (uentry_isAbstractDatatype (e))
    {
            uid = usymtab_supAbstractTypeEntry (e, FALSE);
    }
  else
    {
            uid = usymtab_supEntryAux (globtab, e, FALSE);
    }

  if (sRef_modInFunction ())
    {
      recordFunctionType (globtab->entries[uid]);
    }

    return (globtab->entries[uid]);
}

usymId
usymtab_supAbstractTypeEntry (/*@only@*/ uentry e, bool dodef)
  /*@globals globtab, filetab@*/
  /*@modifies globtab, e@*/
{
  usymId uid;

  uid = usymtab_supEntryAux (globtab, e, FALSE);

  if (dodef)
    {
      uentry ue = usymtab_getTypeEntry (uid);

      uentry_setDatatype (ue, uid);
    }

  if (context_getFlag (FLG_ACCESSMODULE))
    {
      context_addFileAccessType (uid);
    }

  if (sRef_modInFunction ())
    {
      recordFunctionType (globtab->entries[uid]);
    }

  return (uid);
}

# ifndef NOLCL
usymId
usymtab_supExposedTypeEntry (/*@only@*/ uentry e, bool dodef)
  /*@globals globtab, filetab@*/
  /*@modifies globtab, e@*/
{
  usymId uid;

  uid = usymtab_supEntryAux (globtab, e, FALSE);

  if (dodef)
    {
      uentry ue = usymtab_getTypeEntry (uid);

      uentry_setDatatype (ue, uid);
    }

  if (sRef_modInFunction ())
    {
      recordFunctionType (globtab->entries[uid]);
    }

  return (uid);
}
# endif

ctype
usymtab_supForwardTypeEntry (/*@only@*/ uentry e)
  /*@globals globtab, filetab@*/
  /*@modifies globtab, e@*/
{
  usymId uid = usymtab_supEntryAux (globtab, e, FALSE);
  uentry ue = usymtab_getTypeEntry (uid);

    uentry_setDatatype (ue, uid);

  if (sRef_modInFunction ())
    {
      recordFunctionType (globtab->entries[uid]);
    }

  return (uentry_getAbstractType (ue));
}

void
  usymtab_supEntrySref (uentry e)
  /*@globals utab, globtab, filetab@*/
  /*@modifies utab, globtab, e@*/
{
  sRef old = uentry_getSref (e);

  
  if (sRef_isType (old))
    {
      uentry ue = usymtab_supEntryReturnAux (utab, e, TRUE);

      /*@access uentry@*/
      if (uentry_isValid (ue)) 
        {
          sRef uref = uentry_getSref (ue);

          sRef_mergeStateQuiet (uref, old); 
          sRef_clearDerived (uref);
        }
      /*@noaccess uentry@*/
    }
  else if (sRef_isKnown (old))
    {
      usymtab_supEntry (e);
    }
  else
    {
      (void) usymtab_supEntryAux (utab, e, TRUE);
    }
}

void usymtab_supGlobalEntry (/*@only@*/ uentry e)
  /*@globals globtab, filetab@*/
  /*@modifies globtab, filetab, e@*/
{
  usymId uid;

  DPRINTF (("Sup global entry: %s", uentry_unparse (e)));

  uid = usymtab_supEntryAux (globtab, e, FALSE);

  if (sRef_modInFunction ())
    {
      recordFunctionType (globtab->entries[uid]);
    }
}

uentry
  usymtab_supReturnFileEntry (/*@only@*/ uentry e)
  /*@globals filetab, globtab@*/
  /*@modifies filetab, globtab, e@*/
{
  llassert (filetab != usymtab_undefined);
  DPRINTF (("File entry: %s", uentry_unparse (e)));
  return (usymtab_supEntryReturnAux (filetab, e, FALSE));
}

/*
** observers
*/

bool
usymtab_inDeepScope () /*@globals utab@*/
{
  return (utab->lexlevel > paramsScope);
}

static int
usymtab_getIndex (/*@notnull@*/ usymtab s, cstring k)
{
  int i;

  if (s->htable != NULL)
    {
      i = hashTable_lookup (s->htable, k);

      return i;
    }
  else
    {
      for (i = 0; i < s->nentries; i++)
        {
          uentry current = s->entries[i];

          if (!uentry_isUndefined (current) 
              && cstring_equal (uentry_rawName (current), k))
            {
              return i;
            }
        }

      return NOT_FOUND;
    }
}

static uentry
usymtab_fetchIndex (/*@notnull@*/ usymtab s, int i)
{
  llassert (i >= 0 && i < s->nentries);
  return (s->entries[i]);
}

usymId
usymtab_getTypeId (cstring k) /*@globals globtab@*/
{
  usymId uid = usymtab_getIndex (globtab, k);

  if (uid == NOT_FOUND) return USYMIDINVALID;
  if (!(uentry_isDatatype (usymtab_getTypeEntry (uid)))) return USYMIDINVALID;

  return uid;
}

/*@dependent@*/ uentry
usymtab_lookupStructTag (cstring k)
{
  cstring sname = makeStruct (k);
  uentry ue = usymtab_lookupGlob (sname);
    cstring_free (sname);
  return (ue);
}

/*@dependent@*/ uentry
usymtab_lookupUnionTag (cstring k)
{
  cstring uname = makeUnion (k);
  uentry res = usymtab_lookupGlob (uname);

  cstring_free (uname);
  return res;
}

/*@dependent@*/ uentry
usymtab_lookupEnumTag (cstring k)
{
  cstring ename = makeEnum (k);
  uentry res = usymtab_lookupGlob (ename);

  cstring_free (ename);
  return res;
}

usymId
usymtab_getId (cstring k) /*@globals globtab@*/
{
  usymId uid = usymtab_getIndex (globtab, k);
  uentry ue;

  if (uid == NOT_FOUND)
    {
      return USYMIDINVALID;
    }

  ue = usymtab_getGlobalEntry (uid);

  if (uentry_isPriv (ue))
    {
      return USYMIDINVALID;
    }

  return uid;
}

static /*@exposed@*/ uentry 
usymtab_getEntryAux (/*@notnull@*/ usymtab s, usymId uid)
{
  llassert (uid != USYMIDINVALID);
 
  if (uid < 0 || uid >= s->nentries)
    {
      llcontbug (message ("usymtab_getEntry: out of range: level = %d [%d]",
                          s->lexlevel, uid));
      return uentry_undefined;
    }

  llassertprint (uentry_isValid (s->entries[uid]),
                 ("entry undefined: %d", uid));

  return s->entries[uid];
}

/*@dependent@*/ /*@observer@*/ uentry 
  usymtab_getGlobalEntry (usymId uid)
  /*@globals utab, globtab@*/
{
  if (dbgfree) return (uentry_undefined);
  
  if (utab->lexlevel > paramsScope)
    {
      /* need to do this the awkward way, since it could be in conditional scope */
     return (usymtab_lookupSafe (uentry_rawName (globtab->entries[uid])));
    }
  else
    {
      return (globtab->entries[uid]);
    }
}

/*@dependent@*/ /*@exposed@*/ uentry 
  usymtab_getTypeEntry (usymId uid)
  /*@globals globtab@*/
{
  if (dbgload)
    {
      if (uid >= 0 && uid < globtab->nentries)
        {
          return (globtab->entries[uid]);
        }
      else
        {
          return (uentry_undefined);
        }
    }
  else
    {
      llassert (uid >= 0 && uid < globtab->nentries);
      
      return (globtab->entries[uid]);
    }
}

/*
** in load files
*/

/*@dependent@*/ /*@exposed@*/ uentry 
  usymtab_getTypeEntrySafe (usymId uid)
  /*@globals globtab@*/
{
  if (uid < 0 || uid >= globtab->nentries)
    {
      return uentry_undefined;
    }

      return (globtab->entries[uid]);
}

bool
  usymtab_isBoolType (usymId uid)
  /*@globals globtab@*/
{
  llassert (uid >= 0 && uid < globtab->nentries);

  return (cstring_equal (uentry_rawName (globtab->entries[uid]),
                         context_getBoolName ()));
}
 
cstring
usymtab_getTypeEntryName (usymId uid)
   /*@globals globtab@*/
{
  uentry ue;

  if (dbgfree)
    {
      return (cstring_makeLiteral ("<freetype>"));
    }

  ue = usymtab_getTypeEntry (uid);

  if (dbgload && !uentry_isValid (ue))
    {
      return (message ("<missing type: %d>", uid));
    }

  llassertprint (uentry_isValid (ue), ("type undefined: %d", uid));

  return (uentry_getName (ue));
}

static void
usymtab_rehash (/*@notnull@*/ usymtab s)
{
  int i;
  
  if (s->htable != NULL)
    {
      hashTable_free (s->htable);
    }
  
  s->htable = hashTable_create (LLHASHSIZE);

  for (i = 0; i < s->nentries; i++)
    {
      hashTable_insert (s->htable, uentry_rawName (s->entries[i]), i);
    }
}

/*
** superficial copy of usymtab
**
** DO copy spec entries 
*/

static /*@only@*/ /*@notnull@*/ usymtab
usymtab_shallowCopy (/*@notnull@*/ usymtab s) /*@*/
{
  usymtab copytab = usymtab_createRoot ();
  int i;

  for (i = 0; i < s->nentries; i++)
    {
      usymtab_addEntryBase (copytab, s->entries[i]);
    }

  return copytab;
}

static void
usymtab_shallowFree (/*@only@*/ /*@notnull@*/ usymtab s)
{
  aliasTable_free (s->aliases);
  refTable_free (s->reftable, s->nentries);
  sfree (s->entries);
  /*@-compdestroy@*/ sfree (s); /*@=compdestroy@*/
}

/*
** converts usymId from old table to sorted one
*/

usymId 
  usymtab_convertId (usymId uid)
  /*@globals oldtab, utab@*/
{
  uentry ue;
  usymId ret;
  cstring name;

  llassert (usymtab_isDefined (oldtab));

  ue = usymtab_getEntryAux (oldtab, uid);

  llassertprint (uentry_isValid (ue), ("convertId: undefined: %d", uid));

  name = uentry_rawName (ue);

  ret = usymtab_getIndex (utab, name);

  llassertprint (ret != USYMIDINVALID, ("convertId: return is invalid"));

  return (ret);
}

void
usymtab_prepareDump (void)
   /*@globals oldtab, utab@*/
   /*@modifies oldtab, utab@*/
{
  llassert (usymtab_inGlobalScope ());

  llassert (oldtab == usymtab_undefined);

  oldtab = usymtab_shallowCopy (utab);

  /* 
     alpha compare - make sure order is same on different platforms
     error messages appear in same order 
  */

  qsort (utab->entries, (size_t)utab->nentries, 
         sizeof (*utab->entries), (int (*)(const void *, const void *)) uentry_xcomparealpha);

  usymtab_rehash (utab);
}

void
  usymtab_dump (FILE *fout)
  /*@globals utab, oldtab@*/
{
  int i;
  bool neednl = FALSE;
  uentry lastentry = uentry_undefined;
  ekind lastekind = KINVALID;
  int linelen = 0;

  /*
  ** must call prepareDump first
  */

  llassert (oldtab != usymtab_undefined);

  for (i = 0; i < utab->nentries; i++)
    {
      uentry thisentry = utab->entries[i];
      ekind  thisekind = uentry_getKind (thisentry);

      
      if (uentry_hasRealName (thisentry)) {
        if (thisekind != lastekind)
          {
            if (neednl)
              {
                check (fputc ('\n', fout) == (int) '\n');
              }
            
            neednl = FALSE;
            lastentry = uentry_undefined;
            fprintf (fout, "*%d (%s)\n", ekind_toInt (thisekind),  
                     cstring_toCharsSafe (ekind_capName (thisekind)));
            lastekind = thisekind;
            linelen = 0;
          }
        
        if (uentry_isInvalid (lastentry) || !uentry_equiv (lastentry, thisentry)
            || (linelen > (MAX_DUMP_LINE_LENGTH - (2 * MAX_NAME_LENGTH))))
          {
            cstring cdump = uentry_dump (thisentry);
            
            lastentry = thisentry;
            if (neednl)
              {
                check (fputc ('\n', fout) == (int) '\n');
                linelen = 0;
              }
            
            linelen += cstring_length (cdump);
            
            /* no new line here! */
            if (cstring_length (cdump) > 0) 
              {
                check (fputs (cstring_toCharsSafe (cdump), fout) != EOF);
              }
            
            cstring_free (cdump);
            neednl = TRUE;
          }
        else
          {
            cstring cdump = uentry_rawName (thisentry);
                    linelen += cstring_length (cdump);
            fprintf (fout, "#%s", cstring_toCharsSafe (cdump));
          }
      }
    }

  if (neednl)
    {
      check (fputc ('\n', fout) == (int) '\n');
    }
}

void usymtab_load (FILE *f)
  /*@globals utab, globtab@*/
  /*@modifies utab, *f@*/
{
  char *s = mstring_create (MAX_DUMP_LINE_LENGTH);
  char *os = s;
  ekind kind = KINVALID;
  fileloc loc = g_currentloc;
  char c;
  uentry ue;

  dbgload = TRUE;

  llassert (utab == globtab);
  llassert (utab->nentries == 0);

  while (fgets (s, MAX_DUMP_LINE_LENGTH, f) != NULL 
         && *s == ';')
    {
      ; /* ignore ;-comments */
    }

  while (s != NULL && *s != ';')
    {
      
      if (*s == '*')
        {
          s++;
          kind = ekind_fromInt (getInt (&s));

                  goto nextiter;
        }

      if (*s == '$')
        {
          llfatalerror
            (cstring_makeLiteral 
             ("Library is in obsolete format.  Use lclint +whichlib "
              "to see which library is being loaded."));
        }

      ue = uentry_undump (kind, loc, &s);
      DPRINTF (("Load: %s", uentry_unparseFull (ue)));

      if (uentry_isValid (ue))
        {       
          ue = usymtab_addEntryBase (utab, ue);
          /*@-branchstate@*/ 
        } 
      /*@=branchstate@*/

      /*
      ** now, any other names are the same uentry
      */

      while (*(s++) == '#')
        {
          cstring name = cstring_fromCharsO (getWord (&s));
          uentry nue = uentry_nameCopy (name, ue);

          DPRINTF (("Name copy: %s", uentry_unparseFull (nue)));
          usymtab_addEntryBase (utab, nue);
        }

      while ((c = *s) != '\0' && (c !='\n'))
        {
          if (c != ' ' || c != '\t') 
            {
              llbuglit ("Junk in load file");
            }

          s++;
        }

    nextiter:
      s = fgets (os, MAX_DUMP_LINE_LENGTH, f);
    }

  dbgload = FALSE;
  sfree (os);
}

/*
** file scope for static variables
*/

void
usymtab_enterFile ()
  /*@globals utab, globtab, filetab@*/
  /*@modifies filetab@*/
{
  llassert (utab == globtab);

  # if 0
  /* check globals */
  
  usymtab_entries (globtab, ue)
    {
      if (sRef_hasDerived (uentry_getSref (ue)))
        {
          fprintf (g_msgstream, "Derived Global: %s\n", uentry_unparse (ue));
          fprintf (g_msgstream, "sRef: %s\n", sRef_unparseFull (ue->sref));
        }
    } end_usymtab_entries ;

  # endif

  usymtab_enterScope ();
  filetab = utab;
}

void
usymtab_exitFile ()
   /*@globals utab, filetab@*/
   /*@modifies filetab, utab@*/
{
  
  llassert (utab->lexlevel == 1);

  usymtab_exitScope (exprNode_undefined);
  filetab = NULL;
}

void
usymtab_enterScope ()
  /*@globals utab, globtab, filetab@*/
  /*@modifies utab@*/
{
  usymtab t = usymtab_create (US_NORMAL, utab, TRUE);
          
  /* unconditional scope: optimize to avoid copy */
  t->aliases = aliasTable_copy (utab->aliases); 
  utab = t;
  
  llassert (usymtab_isDefined (t->env));
  
  if (t->env->lexlevel == paramsScope && context_inFunctionLike ())
    {
      noshadowerror = TRUE;
      usymtab_handleParams ();
      noshadowerror = FALSE;
    }
}

/*
** setup external references:
**    o only, unique params alias external args
**    o other params may alias anything of their type
*/
 
static void
usymtab_handleParams (void)
  /*@globals utab, globtab, filetab@*/
  /*@modifies utab, globtab@*/
{
  usymtab ptab = utab->env;
  uentry fcn = context_getHeader ();

  
  usymtab_entries (ptab, param)
    {
      uentry ue;

      if (!uentry_isYield (param))
        {
          sRef uref;
          sRef pref = uentry_getSref (param);
          
          llassertprint (uentry_isAnyParam (param), 
                         ("not param: %s", 
                          uentry_unparseFull (param)));
          
          
          ue = uentry_makeVariable (fixParamName (uentry_rawName (param)),
                                    uentry_getType (param),
                                    fileloc_copy (uentry_whereDeclared (param)),
                                    FALSE);

          uentry_copyState (ue, param);
          uentry_setRefParam (ue);
          
          ue = usymtab_supEntrySrefReturn (ue);
                  
          /* must be after supercede! */
          
          if (!sRef_stateKnown (pref))
            {
              uentry_setDefState (ue, SS_DEFINED);
              uentry_setDefState (param, SS_DEFINED);
            }
          else
            {
              if (sRef_isStateSpecial (pref))
                {
                  uentry_setDefState (ue, SS_ALLOCATED);
                }
              else
                {
                  uentry_setDefState (ue, sRef_getDefState (pref));
                }
            }

          uref = uentry_getSref (ue);
          
          if (sRef_isStack (uref))
            {
              alkind pkind = sRef_getAliasKind (pref);

              if (alkind_isKnown (pkind) && !alkind_isLocal (pkind)
                  && !alkind_isStack (pkind))
                {
                  sRef_setAliasKind (uref, pkind, fileloc_undefined);
                  sRef_setOrigAliasKind (uref, pkind);
                }
              else
                {
                  sRef_setAliasKind (uref, AK_IMPTEMP, fileloc_undefined);
                  sRef_setOrigAliasKind (uref, AK_IMPTEMP);

                  if (uentry_isOut (param))
                    {
                      ;
                    }
                  else
                    {
                      sRef_setDefined (uref, fileloc_undefined);
                    }
                }

                    }

                  usymtab_addMustAlias (uref, pref);   

          if (!(uentry_isOnly (param) || uentry_isUnique (param)))
            {
              sRef s = sRef_makeExternal (uref);

                      usymtab_addMustAlias (uref, s);   
            }
          
          if (sRef_isKillRef (pref))
            {
              sRef_setAliasKind (uref, AK_NEWREF, fileloc_undefined);
              sRef_setOrigAliasKind (uref, AK_KILLREF);
            }
          else if (sRef_isRefCounted (uref))
            {
              sRef_setOrigAliasKind (uref, AK_REFCOUNTED);
            }
          else
            {
              /* was AK_UNIQUE */
              sRef_setOrigAliasKind (uref, AK_LOCAL);
            }
        }
      else
        {
                }
    } end_usymtab_entries;


  if (uentry_hasSpecialClauses (fcn))
    {
      specialClauses clauses = uentry_getSpecialClauses (fcn);

      specialClauses_preElements (clauses, cl)
        {
          sRefSet refs = specialClause_getRefs (cl);
          sRefMod modf = specialClause_getEntryFunction (cl);

          
          sRefSet_elements (refs, el)
            {
              sRef base = sRef_getRootBase (el);
              
              if (sRef_isResult (base))
                {
                  ; /* nothing to do before */
                }
              else if (sRef_isParam (base))
                {
                  if (modf != NULL)
                    {
                      sRef sb = sRef_updateSref (el);
                      sRefSet aliases = usymtab_allAliases (sb);
                      
                                      modf (sb, fileloc_undefined);
                                      
                      sRefSet_elements (aliases, sr)
                        {
                                                  modf (sr, fileloc_undefined);
                                                } end_sRefSet_elements ;

                      sRefSet_free (aliases);
                    }
                }
              else
                {
                  if (sRef_isValid (base))
                    {
                      BADBRANCH;
                    }
                }
            } end_sRefSet_elements ;      
        } end_specialClauses_preElements ;
    }
  }
  
void
usymtab_enterFunctionScope (uentry fcn)
  /*@globals utab, filetab, globtab@*/
  /*@modifies utab@*/
{
  usymtab t = usymtab_create (US_NORMAL, utab, TRUE);

  if (utab->lexlevel != fileScope)
    {
      if (utab->lexlevel > fileScope)
        {
          llparseerror (cstring_makeLiteral ("New function scope inside function."));
          
          while (utab->lexlevel > fileScope)
            {
              /*@i@*/ utab = usymtab_dropEnv (utab);
              /*@-branchstate@*/
            }
          /*@=branchstate@*/
        }
      else
        {
          llfatalbug (cstring_makeLiteral ("New function not inside file."));
        }
    /*@-branchstate@*/ } /*@=branchstate@*/

  globSet_allElements (uentry_getGlobs (fcn), el)
    {
      
      if (sRef_isUndefGlob (el))
        {
          int index = sRef_getScopeIndex (el);
          sRef sr = sRef_updateSref (el);
          fileloc loc = uentry_whereEarliest (fcn);
          
          if (sRef_isFileStatic (el))
            {
              ctype ct = sRef_getType (el);
              uentry ue;
              
              llassert (usymtab_isDefined (filetab));

              ue = usymtab_fetchIndex (filetab, index);
              
              if (ctype_isRealArray (ct) || ctype_isRealSU (ct))
                {
                  sRef_setAllocated (sr, loc);
                }
              else
                {
                  sRef_setUndefined (sr, loc);
                }
            }
          else
            {
              uentry ue = globtab->entries[index];
              ctype ct = uentry_getType (ue);
              
              if (ctype_isArray (ct) || ctype_isSU (ct))
                {
                  sRef_setAllocated (sr, loc);
                }
              else
                {
                  sRef_setUndefined (sr, loc);
                }
            }
        }
      else if (sRef_isAllocated (el))
        {
          sRef sr = sRef_updateSref (el);
          fileloc loc = uentry_whereEarliest (fcn);
          
          sRef_setAllocated (sr, loc);
        }
      else if (sRef_isPartial (el))
        {
          sRef sr = sRef_updateSref (el);
          fileloc loc = uentry_whereEarliest (fcn);

          sRef_setPartial (sr, loc);
        }
      else
        {
          /* defined */ ;
        }
    } end_globSet_allElements;

  utab = t;
}

static void
usymtab_caseBranch (void)
  /*@modifies utab@*/
{
  usymtab t = usymtab_create (US_CBRANCH, utab, FALSE);
  utab = t;
}

void
usymtab_switchBranch (/*@unused@*/ exprNode s)
  /*@modifies utab@*/
{
  usymtab t = usymtab_create (US_SWITCH, utab, FALSE);

  t->aliases = aliasTable_copy (utab->aliases);
    utab = t;
}

void
usymtab_trueBranch (/*@only@*/ guardSet guards)
  /*@modifies utab@*/
{
  usymtab t = usymtab_create (US_TBRANCH, utab, FALSE);

  /*
  ** not true! (could be in a macro)
  **
  ** llassertprint (utab->lexlevel > paramsScope,
  ** ("not in scope: %s", usymtab_unparseLocal ()));
  **
  */

  guardSet_free (t->guards);
  t->guards = guards;

    aliasTable_free (t->aliases);
  t->aliases = aliasTable_copy (utab->aliases);
  
    utab = t;
}

/*
** consider,
** 
**   { int a; if (...) a = 3; < a may be undefined here!
**
*/

void
usymtab_popTrueBranch (exprNode pred, exprNode expr, clause cl)
{
  /*
  ** add a false branch
  ** (could be done more efficiently as a special case, but
  ** it is better to only maintain one version of the code)
  */

  usymtab_altBranch (guardSet_invert (exprNode_getGuards (pred)));
  usymtab_popBranches (pred, expr, exprNode_undefined, TRUE, cl);
}

void
usymtab_popCaseBranch () /*@modifies utab@*/
{
  llassert (utab->kind == US_CBRANCH);
  usymtab_quietPlainExitScope ();
}

void
usymtab_popTrueExecBranch (exprNode pred, exprNode expr, clause cl)
{
  /*
  ** add a false branch that must return --- that is,
  ** the true branch is always executed!
  */
  
  usymtab_altBranch (guardSet_invert (exprNode_getGuards (pred)));
  usymtab_popBranches (pred, expr, exprNode_makeMustExit (), FALSE, cl);
}

void
usymtab_popOrBranch (exprNode pred, exprNode expr)
  /*@modifies utab@*/
{
  bool mustReturn;
  usymtab env = utab->env;
  usymtab otab = utab;
  int i = 0;

  llassert (env != NULL);

  if (exprNode_isError (expr))
    {
      mustReturn = FALSE;
    }
  else
    {
      mustReturn = exprNode_mustEscape (expr);
    }

  
  llassert (utab->kind == US_TBRANCH);

  /*
  ** merge each entry in table with its original
  ** unless execution cannot continue after this branch
  */

  for (i = 0; i < utab->nentries; i++)
    {
      uentry current = utab->entries[i];
      uentry old = usymtab_lookupAux (env, uentry_rawName (current));

      uentry_mergeState (old, current, exprNode_loc (expr), 
                         mustReturn, FALSE, TRUE, ORCLAUSE);
    }
  
  
  if (mustReturn)
    {
      env->guards = guardSet_levelUnionFree (env->guards, 
                                             guardSet_invert (exprNode_getGuards (pred)), 
                                             env->lexlevel);
    }
  else
    {
      env->aliases = aliasTable_levelUnion (env->aliases, otab->aliases, env->lexlevel);
    }
 
  /* env is now utab */
  usymtab_quietPlainExitScope ();
}

/*
** case syntax in C is very unrestricted.  This is unfortunate.
**
** A switch case is ended either by a new case or default, or
** a close } that may close the switch or some other control
** structure.  
*/

bool
usymtab_newCase (/*@unused@*/ exprNode pred, exprNode last)
  /*@modifies utab@*/
{
  bool mustBreak = usymtab_mustBreak (utab);
  bool mustReturn = usymtab_mustEscape (utab);
  usymtab stab = utab;

  /*
  ** Find last case (or outer switch)
  */

  while (stab->kind != US_CBRANCH && stab->kind != US_SWITCH)
    {
      stab = stab->env;
      llassert (stab != GLOBAL_ENV);
    }

  /* ??? */

  while (stab->kind == US_CBRANCH)
    {
      stab = stab->env;
      llassert (stab != GLOBAL_ENV);
    }
  
  /*
  ** if its a fall through case, merge in outside entries and last case.
  **
  ** e.g.,
  **        ...
  **        switch
  **          case 1: x = 3; <fall through>
  **          case 2: << x may not be defined
  **
  */

  if (!mustBreak && !mustReturn && utab->kind == US_CBRANCH)
    {
      llassert (stab->kind == US_SWITCH || stab->kind == US_NORMAL);

      usymtab_entries (utab, ue)  /* but, keep track of used variables */
        {
          uentry old = usymtab_lookupAux (stab, uentry_rawName (ue));

          llassert (uentry_isValid (old));

          /* modifies ue, not old */
          
          uentry_mergeState (ue, old, exprNode_loc (last),
                             FALSE, FALSE, TRUE, CASECLAUSE); 
        } end_usymtab_entries;

      utab->aliases = aliasTable_levelUnion (utab->aliases, 
                                             stab->aliases, utab->lexlevel);
      
      /* 
      ** No need for a new branch.
      */
      
      return FALSE;
    }
  else
    {
      usymtab_caseBranch ();
      /*@-mustfree@*/ /*< utab->aliases >*/
      utab->aliases = aliasTable_copy (stab->aliases);
      /*@=mustfree@*/
      
      return TRUE;
    }
}

/*
** for && (both pred and expr are executed)
*/

void
usymtab_popAndBranch (exprNode pred, /*@unused@*/ exprNode expr)
  /*@modifies utab@*/
{
  usymtab env = utab->env;
  usymtab otab= utab;
  int i = 0;

    llassert (utab->kind == US_TBRANCH);

  /*
  ** merge each entry in table with its original
  ** unless execution cannot continue after this branch
  */

  for (i = 0; i < utab->nentries; i++)
    {
      uentry current = utab->entries[i];
      sRef   tref = uentry_getSref (current);
      uentry old = usymtab_lookupAux (env, uentry_rawName (current));
      sRef   oref = uentry_getSref (old);

      /* note that is current is in a nested branch,
         it may create a "new" old entry. */

      llassert (uentry_isValid (old));
      uentry_mergeState (old, current, exprNode_loc (expr), 
                         FALSE, FALSE, TRUE, ANDCLAUSE);

      /*
      ** if is it defined by the second clause, then it should be defined.
      */

      if (sRef_isAnyDefined (tref)
          && (sRef_isAllocated (oref) || sRef_isStateUndefined (oref)))
        {
          sRef_setDefined (oref, g_currentloc);
        }
    }

  utab->guards = guardSet_levelUnionFree (utab->guards, 
                                          guardSet_invert (exprNode_getGuards (pred)), 
                                          utab->lexlevel);
  utab->aliases = aliasTable_levelUnion (utab->aliases, otab->aliases, utab->lexlevel);

  usymtab_quietPlainExitScope ();

  }

/*
** Stack should be [ US_CBRANCH+ US_SWITCH ]
** Only branches which do not return (except possibly the last branch) are included.
**
** Conditionally merge state from all CBRANCHes.
**
** If allpaths is TRUE, then all possible executions go through some switch 
** case, and the original scope is not merged.
*/

void
usymtab_exitSwitch (/*@unused@*/ exprNode sw, bool allpaths)
  /*@modifies utab@*/
{
  usymtab ttab = utab;
  usymtab stab = ttab;
  usymtab ltab = ttab;
  bool lastMustReturn = usymtab_mustEscape (utab);
  int i;
  
    
  while (stab->kind == US_CBRANCH)
    {
      stab = stab->env;
      llassert (stab != GLOBAL_ENV);
    }

  while (stab->kind == US_NORMAL)
    {
      stab = stab->env;
      llassert (stab != GLOBAL_ENV);
    }

  llassert (stab->kind == US_SWITCH);

  /* go to the scope outside the switch (US_SWITCH is just a marker! */
  stab = stab->env; 
  llassert (stab != GLOBAL_ENV);

  
  ttab = ttab->env;
  llassert (usymtab_isDefined (ttab));
  
  if (ttab->kind == US_CBRANCH)
    {
      /* was quietPlainExitScope --- but, can't free it yet! */
      utab = utab->env;
      llassert (utab != GLOBAL_ENV);

      while (ttab->kind == US_CBRANCH)
        {
          /*
          ** (from popTrueBranch)
          */      
          
          bool mustReturn = usymtab_mustEscape (ttab);
          bool mustBreak = usymtab_mustBreak (ttab);
          
          usymtab_entries (ttab, current)
            {
              uentry old = /*@-compmempass@*/ usymtab_lookupAux (ltab, uentry_rawName (current));
                           /*@=compmempass@*/ 
              
              /*
              ** note that is this is in a nested branch,
              ** it may create a "new" old entry. 
              */
           
              if (uentry_isValid (old))
                {
                  if (lastMustReturn)
                    {
                      uentry_mergeUses (current, old);
                      uentry_setState (old, current);
                    }
                  else
                    {
                      uentry_mergeState (old, current, exprNode_loc (sw),
                                         mustReturn, FALSE, TRUE, SWITCHCLAUSE);
                    }
                }
              else
                {
                  ;
                }
            } end_usymtab_entries;
          
          /*
          ** if entry is not in symbol table for this case, merge with pre-switch
          ** table
          */
          
          if (!mustReturn && !mustBreak)
            {
              usymtab_entries (stab, current)
                {
                  if (usymtab_getIndex (ttab, uentry_rawName (current)) == NOT_FOUND)
                    {
                      uentry old = /*@-compmempass@*/
                        usymtab_lookupAux (ltab, uentry_rawName (current));
                      /*@=compmempass@*/

                      llassert (uentry_isValid (old));
                      uentry_mergeState (old, current, exprNode_loc (sw),
                                         FALSE, FALSE, TRUE, SWITCHCLAUSE);
                    }
                } end_usymtab_entries;
            }
          
          ltab->env = ttab->env; 
          ttab = ltab->env;

          /*
          ** Suprious error, becuase of environments.
          */

          /*@i1@*/ utab = ltab;

          lastMustReturn = FALSE;
          /*@-branchstate@*/ 
        }
    }
  /*@=branchstate@*/

  /*
  ** now, there is one US_CBRANCH.  Merge this with the stab.
  */
  
    
  for (i = 0; i < ltab->nentries; i++)
    {
      uentry current = ltab->entries[i];
      uentry old = usymtab_lookupAux (stab, uentry_rawName (current));
      
      /* note that is this is in a nested branch,
         it may create a "new" old entry. */
      
         
      if (uentry_isValid (old))
        {
          if (allpaths)
            {
              uentry_mergeUses (current, old);
              uentry_setState (old, current);
            }
          else
            {
              uentry_mergeState (old, current, exprNode_loc (sw), 
                                 FALSE, FALSE, TRUE, SWITCHCLAUSE);
            }
        }
      else
        {
                }
    }
  
  /*
  ** exit the switch
  */
  
  
  /*
  ** switch may or may not be followed by a new scope
  */

  if (utab->kind == US_SWITCH)
    {
      usymtab_quietPlainExitScope ();  
    }
  else
    {
      usymtab_quietPlainExitScope ();
      llassert (utab->kind == US_SWITCH);
      usymtab_quietPlainExitScope ();   
    }

  }

static void 
updateNullState (sRef el, /*@notnull@*/ usymtab ttab, 
                 /*@notnull@*/ usymtab ftab, bool trueGuard)
{
  sRef base = sRef_getRootBase (el);
  int level = sRef_lexLevel (base);
  
        
    
  if (sRef_isCvar (base))
    {
      usymId index = sRef_getScopeIndex (base);
      uentry ue = usymtab_getRefTab (ttab, level, index);

      if (!uentry_isLset (ue)) 
        {
          sRef sr = uentry_getSref (ue);

          if (trueGuard)
            {
              sRef_setDerivNullState (sr, el, NS_NOTNULL);
            }
          else 
            {
              if (!guardSet_isGuarded (ttab->guards, el) 
                  && !sRef_isNotNull (sr))
                {
                  sRef_setDerivNullState (sr, el, NS_DEFNULL);
                                }
            }
        }
      else
        {
                }
      
      ue = usymtab_getRefTab (ftab, level, index);
      
      if (!uentry_isLset (ue)) 
        {
          sRef sr = uentry_getSref (ue);
          
          
          if (!trueGuard) /* yikes!  forgot the ! */
            {
              sRef_setDerivNullState (sr, el, NS_NOTNULL);
            }
          else 
            {
              
              if (!guardSet_isGuarded (ftab->guards, el)
                  && !sRef_isNotNull (sr))
                {
                  sRef_setDerivNullState (sr, el, NS_DEFNULL);
                                }
            }
        }
      else
        {
                }
      
          }

      }

void
usymtab_popBranches (exprNode pred, exprNode tbranch, exprNode fbranch, 
                     bool isOpt, clause cl)
     /*@modifies utab@*/
{
  int i = 0;
  usymtab ftab = utab;
  usymtab ttab = utab->env;

  fileloc loc;
  usymtab env;
  guardSet guards = exprNode_getGuards (pred);
  sRefSet tguards = guardSet_getTrueGuards (guards);
  sRefSet fguards = guardSet_getFalseGuards (guards);
  bool mustReturnT = exprNode_mustEscape (tbranch);
  bool mustReturnF = exprNode_mustEscape (fbranch);
  
  if (exprNode_isDefined (fbranch))
    {
      loc = exprNode_loc (fbranch);
    }
  else
    {
      loc = exprNode_loc (tbranch);
    }

  llassert (usymtab_isDefined (ttab));
  
  env = ttab->env;
  
  llassert (usymtab_isDefined (env));
  llassert (ftab->kind == US_FBRANCH);
  llassert (ttab->kind == US_TBRANCH);

  /*
  ** For each element that is true guarded (i.e., if (x != NULL)) 
  **          make x = null in false branch,
  **          and x = notnull in true branch.
  **          unless x was set locally in that branch.
  ** For each element that is false guarded (x == NULL) 
  **          make x = null in true, notnull in false.
  **                      
  ** For each element that is either guarded (pred(x)) 
  **     
  */
  
  sRefSet_allElements (tguards, el)
    {
      updateNullState (el, ttab, ftab, TRUE);
    } end_sRefSet_allElements;
    
  sRefSet_allElements (fguards, el)
    {
      updateNullState (el, ttab, ftab, FALSE);
    } end_sRefSet_allElements;

  /*
  ** 
  ** if an entry is in both true and false, merge the entries,
  ** then replace original with new state.
  **
  ** if an entry is in one table, merge it with the original.
  */
    
  for (i = 0; i < ftab->nentries; i++)
    {
      uentry fthis = ftab->entries[i];
      uentry old = usymtab_lookupAux (env, uentry_rawName (fthis));
      int    tindex = usymtab_getIndex (ttab, uentry_rawName (fthis));
      
      if (uentry_isUndefined (old))
        {
          /* possible entry was added as an undefined id */
          continue;
        }
      
      if (tindex != NOT_FOUND)
        {
          uentry tthis = ttab->entries[tindex];
          
          /* note that is this is in a nested branch,
             it may create a "new" old entry. */
          
          if (!mustReturnF)
            {
              if (!mustReturnT)
                {
                  
                  uentry_mergeState (fthis, tthis, loc,
                                     mustReturnT, FALSE, FALSE, cl);
                }
              else
                {
                  uentry_mergeUses (fthis, tthis);
                }
              
              uentry_setState (old, fthis);
              
              /*@-mustfree@*/ 
            } 
          /*@=mustfree@*/
          else
            {
              uentry_setState (old, tthis);
              uentry_mergeState (old, fthis, loc, mustReturnF, 
                                 TRUE, FALSE, cl);
            }
          
          ttab->entries[tindex] = uentry_undefined;
          uentry_free (tthis);
        }
      else
        {
          uentry_mergeState (old, fthis, loc, mustReturnF, TRUE, FALSE, cl);
        }
    }

  for (i = 0; i < ttab->nentries; i++)
    {
      uentry current = ttab->entries[i];
      
      if (!uentry_isUndefined (current)) 
        {
          uentry old = usymtab_lookupAux (env, uentry_rawName (current));

          llassertprint (!uentry_isUndefined (old), ("name: <%s>", 
                                                     uentry_rawName (current)));
          if (mustReturnF)
            {
              uentry_mergeUses (current, old); 
              uentry_setState (old, current);
            }
          else
            {
              /*
              ** assumes false branch is a fall-through if
              ** fbranch is not defined.  This is true, unless
              ** where was some greivous error in processing
              ** the else branch of an if-then, in which case
              ** this is probably the right thing to do anyway.
              */

              uentry_mergeState (old, current, loc, mustReturnT, 
                                 FALSE, isOpt, cl);
            }
        }
    }

  
  /*
  ** Plain levelUnion doesn't work, since we need to use the sRef's in env->aliases
  ** if they are present.
  */

  llassert (NOALIAS (env->aliases, ttab->aliases));
  llassert (NOALIAS (env->aliases, ftab->aliases));

  aliasTable_free (env->aliases);  

  env->aliases = aliasTable_levelUnionNew (ttab->aliases, 
                                           ftab->aliases, env->lexlevel);

  aliasTable_fixSrefs (env->aliases);
  
  /* exit true and false scopes */
  usymtab_quietPlainExitScope ();
  usymtab_quietPlainExitScope ();
  
  if (mustReturnT)
    {
      utab->guards = guardSet_levelUnionFree 
        (utab->guards, 
         guardSet_invert (exprNode_getGuards (pred)), 
         utab->lexlevel);
    }

  if (mustReturnF)
    {
      utab->guards = guardSet_levelUnion (utab->guards, 
                                          exprNode_getGuards (pred), 
                                          utab->lexlevel);
    }

  DPRINTF (("Here."));
}

static void usymtab_fixCases (void) /*@modifies utab@*/ {
  while (utab->kind == US_CBRANCH)
    {
      usymtab_quietPlainExitScope ();
    }

  llassert (utab->kind != US_CBRANCH);
}

void
usymtab_altBranch (/*@only@*/ guardSet guards)
  /*@modifies utab@*/
{
  usymtab t = usymtab_create (US_FBRANCH, utab, FALSE);
  usymtab parent = utab->env;

  /*
  ** If we are in a case, need to close it.  The C syntax
  ** is very liberal, so this kludge is necessary.
  */

  usymtab_fixCases ();

  DPRINTF (("Current kind: %s", usymtab_unparseStack ()));
  llassert (utab->kind == US_TBRANCH);
  llassert (parent != GLOBAL_ENV);

  guardSet_free (t->guards);
  t->guards = guards;

  aliasTable_free (t->aliases);
  t->aliases = aliasTable_copy (parent->aliases);
    
  utab = t;
}

void
usymtab_allDefined (void)
   /*@globals utab, globtab@*/
{
  int i;

  llassert (utab == globtab);

  for (i = 0; i < utab->nentries; i++)
    {
      uentry e = utab->entries[i];

      if (uentry_isPriv (e))
        {
         ; /* no need to define it */
        }
      else
        {
          if (context_getFlag (FLG_SPECUNDECL))
            {
              fileloc sloc = uentry_whereSpecified (e);
              fileloc dloc = uentry_whereDeclared (e);

              if (fileloc_isDefined (sloc) 
                  && !uentry_isFakeTag (e)
                  && !fileloc_isDefined (dloc))
                {
                  voptgenerror 
                    (FLG_SPECUNDECL,
                     message ("%s %q specified but not declared",
                              ekind_capName (uentry_getKind (e)),
                              uentry_getName (e)),
                     sloc);
                }
            }
          
          if (!uentry_isCodeDefined (e))
            {
              fileloc dloc = uentry_whereDeclared (e);
              
              if (fileloc_isLib (dloc))
                {
                 ;
                }
              else if (fileloc_isDefined (dloc))
                {
                  if (!uentry_isAnyTag (e))
                    {
                      if (fileloc_isUser (dloc))
                        {
                          voptgenerror 
                            (FLG_DECLUNDEF,
                             message ("%s %q declared but not defined",
                                      ekind_capName (uentry_getKind (e)),
                                      uentry_getName (e)),
                             dloc);
                        }
                    }
                }
              else
                {
                  fileloc sloc = uentry_whereSpecified (e);

                  if (fileloc_isDefined (sloc) 
                      && !fileloc_isImport (sloc)
                      && !fileloc_isLib (sloc)
                      && !fileloc_isPreproc (sloc)
                      && !uentry_isFakeTag (e))
                    {
                      if (uentry_isVariable (e) || uentry_isFunction (e))
                        {
                          voptgenerror 
                            (FLG_SPECUNDEF,
                             message ("%s %q specified but not declared or defined",
                                      ekind_capName (uentry_getKind (e)),
                                      uentry_getName (e)),
                             sloc);
                        }
                      else
                        {
                          voptgenerror 
                            (FLG_SPECUNDEF,
                             message ("%s %q specified but not defined",
                                      ekind_capName (uentry_getKind (e)),
                                      uentry_getName (e)),
                             sloc);
                        }
                    }
                }
            }
        }
    }
}

void usymtab_exportHeader (void)
     /*@globals utab@*/
{
  int i;

  for (i = 0; i < utab->nentries; i++)
    {
      uentry ce = utab->entries[i];

      if (!uentry_isDatatype (ce) 
          && !uentry_isAnyTag (ce) 
          && !uentry_isEitherConstant (ce) && !uentry_isStatic (ce)
          && !uentry_isExternal (ce)
          && !uentry_isForward (ce))
        {
          fileloc fwhere = uentry_whereDeclared (ce);

          if (fileloc_isUndefined (fwhere)
              && uentry_isFunction (ce))
            {
              fwhere = uentry_whereDefined (ce);
            }

          if (fileloc_isDefined (fwhere) 
              && !fileloc_isHeader (fwhere)
              && !(fileloc_isSpecialFile (fwhere)
                   && !context_getFlag (FLG_UNUSEDSPECIAL)))
            {
              if (uentry_isVariable (ce))
                {
                  if (optgenerror
                      (FLG_EXPORTHEADERVAR,
                       message ("%s %q exported but not declared in header file", 
                                ekind_capName (uentry_getKind (ce)),
                                uentry_getName (ce)),
                       fwhere))
                    {
                      uentry_showDefSpecInfo (ce, fwhere);
                    }
                }
              else
                {
                  if (!uentry_isIter (ce)
                      && !uentry_isEndIter (ce)
                      && !uentry_isExpandedMacro (ce))
                    {
                      if (uentry_isFunction (ce) 
                          && cstring_equalLit (uentry_rawName (ce), "main"))
                        {
                          ; /* no error for main */
                        }
                      else
                        {
                          if (optgenerror
                              (FLG_EXPORTHEADER,
                               message ("%s %q exported but not declared "
                                        "in header file", 
                                        ekind_capName (uentry_getKind (ce)),
                                        uentry_getName (ce)),
                               fwhere))
                            {
                              uentry_showDefSpecInfo (ce, fwhere);
                            }
                        }
                    }
                }
            }
        }
    }
}

void usymtab_exportLocal (void)
   /*@globals utab@*/
{
  int i;

  
  for (i = 0; i < utab->nentries; i++)
    {
      uentry ce = utab->entries[i];

      
      if (!uentry_isDatatype (ce) && !uentry_isAnyTag (ce) 
          && !uentry_isEitherConstant (ce) 
          && !uentry_isIter (ce)
          && !uentry_isEndIter (ce)
          && !uentry_isExpandedMacro (ce)
          && uentry_isUsed (ce))
        {
          /* check static uses */
          filelocList fuses = uentry_getUses (ce);
          fileloc mod = uentry_whereDefined (ce);
          bool ok = filelocList_isEmpty (fuses);
          fileloc fwhere = uentry_whereDeclared (ce);

          if (fileloc_isSpecialFile (fwhere)
              && !context_getFlag (FLG_UNUSEDSPECIAL))
            {
              ok = TRUE; /* no errors for special files */
            }
          else
            {
              filelocList_elements (fuses, uloc)
                {
                  if (fileloc_isUndefined (uloc) || !fileloc_sameModule (uloc, mod))
                    {
                      ok = TRUE;
                      /*@innerbreak@*/ break;
                    }
                } end_filelocList_elements;
            }

          if (!ok)
            {
              if (optgenerror
                  (FLG_EXPORTLOCAL,
                   message ("%s exported but not used outside %s: %q", 
                            ekind_capName (uentry_getKind (ce)),
                            fileloc_getBase (mod),
                            uentry_getName (ce)),
                   fwhere))
                {
                  uentry_showDefSpecInfo (ce, fwhere);
                }
            }
        }
    }
}

void
usymtab_allUsed (void)
  /*@globals utab@*/
{
  int i;
  bool isFileStatic = usymtab_inFileScope ();
  cstring last_file = cstring_undefined;

  for (i = 0; i < utab->nentries; i++)
    {
      bool hasError = FALSE;
      uentry ce = utab->entries[i];
      fileloc fwhere = uentry_whereDeclared (ce);

      if (fileloc_isUndefined (fwhere))
        {
          fwhere = uentry_whereDefined (ce);
        }

      if (fileloc_isInvalid (fwhere) 
          || fileloc_isLib (fwhere) 
          || fileloc_isBuiltin (fwhere)
          || ((fileloc_isSpecialFile (fwhere)
               || fileloc_isSpecialFile (uentry_whereDefined (ce)))
              && !context_getFlag (FLG_UNUSEDSPECIAL)))
        {
          ;
        }
      else if (!uentry_wasUsed (ce) && !uentry_isAnyTag (ce))
        {
          cstring fname = fileloc_filename (fwhere);

          if (cstring_isUndefined (last_file))
            {
              last_file = fname;
            }
          else if (cstring_equal (fname, last_file))
            {
            }
          else
            {
              cleanupMessages ();
              last_file = fname;
            } 
          
          if (uentry_isParam (ce))
            {
              if (context_inMacro ())
                {
                  sRef cref = uentry_getSref (ce);

                  if (uentry_isYield (ce))
                    {
                      ; /* no checks (for now) */
                    }
                  else if (sRef_isSafe (cref))
                    {
                      ; /* no error */
                    }
                  else
                    {
                      if (uentry_hasRealName (ce))
                        {
                          hasError = 
                            optgenerror (FLG_MACROPARAMS,
                                         message ("Macro parameter %q not used", 
                                                  uentry_getName (ce)),
                                         fwhere);
                        }
                    }
                }
              else 
                {
                  if (cstring_equalFree (uentry_getName (ce), 
                                         cstring_makeLiteral ("...")))
                    {
                      ;
                    }
                  else
                    {
                      hasError = optgenerror (FLG_PARAMUNUSED,
                                              message ("Parameter %q not used",
                                                       uentry_getName (ce)),
                                              fwhere);
                    }
                }
            } /* isParam */
          else if (uentry_isFunction (ce) || uentry_isIter (ce))
            {
              if (fileloc_isUser (fwhere))
                {
                  hasError = optgenerror
                    (FLG_FUNCUNUSED, 
                     message ("%q %q declared but not used", 
                              cstring_makeLiteral 
                              (uentry_isIter (ce) ? "Iterator" 
                               : (isFileStatic ? "File static function" : "Function")),
                              uentry_getName (ce)),
                     fwhere);
                }
            }
          else if (uentry_isEndIter (ce))
            {
              ; /* no error (already reported for iter */
            }
          else if (uentry_isEnumConstant (ce))
            {
              if (fileloc_isUser (fwhere))
                {
                  hasError = optgenerror
                    (FLG_ENUMMEMUNUSED,
                     message ("Enum member %q not used", 
                              uentry_getName (ce)),
                     fwhere);
                }
            }
          else if (uentry_isConstant (ce))
            {
              if (fileloc_isUser (fwhere))
                {
                  hasError = optgenerror
                    (FLG_CONSTUNUSED,
                     message ("Constant %q declared but not used", 
                              uentry_getName (ce)),
                     fwhere);
                }
            }
          else if (uentry_isDatatype (ce))
            {
              if (fileloc_isUser (fwhere))
                {
                  hasError = optgenerror
                    (FLG_TYPEUNUSED,
                     message ("Type %q declared but not used", 
                              uentry_getName (ce)),
                     fwhere);
                }
            }
          else if (!uentry_isRefParam (ce) && !uentry_isExpandedMacro (ce))
            { /* errors for ref params will be reported in the next scope */
              llassertprint (uentry_isVar (ce), 
                             ("ce: %s", uentry_unparseFull (ce)));

              if (ctype_isFunction (uentry_getType (ce)))
                {
                  if (fileloc_isUser (fwhere))
                    {
                      hasError = optgenerror
                        (FLG_FUNCUNUSED,
                         message ("%q %q declared but not used", 
                                  cstring_makeLiteral 
                                  (isFileStatic ? "File static function" 
                                   : "Function"),
                                  uentry_getName (ce)),
                         fwhere);
                    }
                }
              else 
                {
                  if (fileloc_isUser (fwhere))
                    {
                      
                      
                      hasError = optgenerror 
                        (FLG_VARUNUSED,
                         message ("%q %q declared but not used", 
                                  cstring_makeLiteral 
                                  (isFileStatic ? "File static variable" 
                                   : "Variable"), 
                                  uentry_getName (ce)),
                         fwhere);
                    }
                }
            }
          else
            {
              ; /* no errors */
            }
        } /* unused */
      else if (uentry_isDatatype (ce) || uentry_isAnyTag (ce))
        { /* check all fields */
          ctype ct = uentry_getRealType (ce); 

          
          while (ctype_isAP (ct))
            {
              ct = ctype_getBaseType (ct);
            }

          
          if (ctype_isSU (ct))
            {
              uentryList fields = ctype_getFields (ct);

              uentryList_elements (fields, field)
                {
                  if (!uentry_isUsed (field))
                    {
                      if (uentry_hasName (ce))
                        {
                          hasError |= optgenerror 
                            (FLG_FIELDUNUSED,
                             message ("Field %q of %s %q declared but not used", 
                                      uentry_getName (field),
                                      cstring_makeLiteralTemp
                                      (ctype_isStruct (ct) ? "structure" : "union"),
                                      uentry_getName (ce)),
                             uentry_whereEarliest (field));
                        }
                      else
                        {
                          hasError |= optgenerror 
                            (FLG_FIELDUNUSED,
                             message ("Field %q of unnamed %s declared but not used", 
                                      uentry_getName (field),
                                      cstring_makeLiteralTemp
                                      (ctype_isStruct (ct) ? "structure" : "union")),
                             uentry_whereEarliest (field));
                        }
                      
                      uentry_setUsed (field, fileloc_undefined);
                    }
                } end_uentryList_elements;
            }
        }
      else
        {
          ; /* no errors */
        }

      if (hasError)
        {
          if (uentry_isParam (ce) && context_inMacro ())
            {
              if (fileloc_isDefined (uentry_whereSpecified (ce)))
                {
                  uentry_showWhereSpecified (ce);
                }
            }
          else
            {
              uentry_showDefSpecInfo (ce, fwhere);
            }

          uentry_setUsed (ce, fileloc_undefined);
        }
    }
}

static void
checkGlobalReturn (uentry glob, sRef orig)
{
  sRef sr = uentry_getSref (glob);
  
  
  if (context_getFlag (FLG_GLOBSTATE))
    {
      if (sRef_isKilledGlob (orig))
        {
          if (sRef_isStateUndefined (sr)
              || sRef_isUnuseable (sr)
              || sRef_isStateUnknown (sr)
              || sRef_isDead (sr))
            {
              ;
            }
          else
            {
              ctype ct = ctype_realType (uentry_getType (glob));

              if (ctype_isVisiblySharable (ct))
                {
                  if (optgenerror 
                      (FLG_GLOBSTATE,
                       message 
                       ("Killed global %q not released before return",
                        uentry_getName (glob)),
                       g_currentloc))
                    {
                      sRef_showStateInfo (sr);
                                    }
                }
              else
                {
                                  sRef_protectDerivs ();
                  (void) checkGlobalDestroyed (sr, g_currentloc);
                  sRef_clearProtectDerivs ();
                }
            }
        }
      else
        {
          if (sRef_isStateUndefined (sr))
            {
              if (optgenerror (FLG_GLOBSTATE,
                               message 
                               ("Function returns with global %q undefined",
                                uentry_getName (glob)),
                               g_currentloc))
                {
                  sRef_showStateInfo (sr);
                }
            }
          else 
            {
              if (sRef_isDead (sr))
                {
                  if (optgenerror 
                      (FLG_GLOBSTATE,
                       message ("Function returns with global %q "
                                "referencing released storage",
                                uentry_getName (glob)),
                       g_currentloc))
                    {
                      sRef_showStateInfo (sr);
                      sRef_setDefState (sr, SS_UNKNOWN, fileloc_undefined);
                    }
                }
              
              if (ctype_isRealPointer (uentry_getType (glob)) &&
                  sRef_possiblyNull (sr) && !uentry_possiblyNull (glob))
                {
                  if (optgenerror 
                      (FLG_GLOBSTATE,
                       message ("Function returns with non-null global %q "
                                "referencing null storage",
                                uentry_getName (glob)),
                       g_currentloc))
                    {
                      sRef_showNullInfo (sr);
                    }
                }
              else
                {
                  checkGlobReturn (glob);
                }
            }
        }
    }
}

/*
** remember: check alias globals
*/

void usymtab_checkFinalScope (bool isReturn)
  /*@globals utab@*/
{
  bool mustFree = context_getFlag (FLG_MUSTFREE);
  bool mustDefine = context_getFlag (FLG_MUSTDEFINE);
  /* bool mustNotAlias = context_getFlag (FLG_MUSTNOTALIAS); */
  sRefSet checked = sRefSet_new ();
  usymtab stab = utab;
  int i;
    
  /*
  ** need to check all scopes out to function parameters.
  */

  do 
    {
      for (i = 0; i < stab->nentries; i++)
        {
          uentry ce = stab->entries[i];
          sRef sr = uentry_getSref (ce);
          sRef rb = sRef_getRootBase (sr);

          if (ctype_isFunction (uentry_getType (ce)))
            {
              /*@innercontinue@*/ continue;
            }

          if (mustFree)
            {
              DPRINTF (("Check entry: %s", uentry_unparseFull (ce)));

              if (!sRefSet_member (checked, sr) && !sRef_isGlobal (rb))
                {
                  if (ctype_isRealSU (uentry_getType (ce))
                      && !uentry_isAnyParam (ce)
                      && !uentry_isRefParam (ce)
                      && !uentry_isStatic (ce)
                      && !sRef_isDependent (sr)
                      && !sRef_isOwned (sr))
                    {
                      sRefSet als = usymtab_allAliases (sr);

                      
                      if (sRefSet_isEmpty (als))
                        {
                          checkLocalDestroyed (sr, g_currentloc);
                        }
                      else
                        {
                          /* aliased, no problem */ ;
                        }

                      sRefSet_free (als);
                    }
                  else if
                    (!uentry_isStatic (ce)
                     && ((sRef_isNewRef (sr))
                         || (((sRef_isOnly (sr) || sRef_isFresh (sr) 
                               || sRef_isKeep (sr) || sRef_isOwned (sr))
                              && !sRef_isDead (sr))
                             && (!sRef_definitelyNull (sr))
                             && (!usymtab_isProbableNull (sr)))))
                      {
                        bool hasError = TRUE;
                        
                        /*
                        ** If its a scope exit, check if there is an alias.
                        ** If so, make it only.  If not, there is an error.
                        */
                        
                        if (!isReturn)
                          {
                            if (canLoseReference (sr, g_currentloc))
                              {
                                hasError = FALSE;
                              }
                          }
                        
                        if (hasError)
                          {
                            if (sRef_hasLastReference (sr))
                              {
                                sRef ar = sRef_getAliasInfoRef (sr);
                                
                                if (optgenerror 
                                    (FLG_MUSTFREE,
                                     message
                                     ("Last reference %q to %s storage %qnot %q before %q",
                                      sRef_unparse (sr),
                                      alkind_unparse (sRef_getAliasKind (sr)),
                                      sRef_unparseOpt (ar),
                                      cstring_makeLiteral (sRef_isKeep (sr) 
                                                           ? "transferred" : "released"),
                                      cstring_makeLiteral (isReturn 
                                                           ? "return" : "scope exit")),
                                     g_currentloc))
                                  {
                                    sRef_showRefLost (sr);
                                  }
                              }
                            else if (sRef_isNewRef (sr))
                              {
                                if (optgenerror
                                    (FLG_MUSTFREE,
                                     message 
                                     ("%q %q not released before %q",
                                      cstring_makeLiteral 
                                      (alkind_isKillRef (sRef_getOrigAliasKind (sr))
                                       ? "Kill reference parameter" : "New reference"),
                                      uentry_getName (ce),
                                      cstring_makeLiteral (isReturn
                                                           ? "return" : "scope exit")),
                                     g_currentloc))
                                  {
                                    sRef_showAliasInfo (sr);
                                  }
                              }
                            else 
                              {
                                if (ctype_isRealSU (sRef_getType (sr)))
                                  {
                                                                    checkStructDestroyed (sr, g_currentloc);
                                  }
                                else
                                  {
                                    if (optgenerror
                                        (FLG_MUSTFREE,
                                         message 
                                         ("%s storage %q not %q before %q",
                                          alkind_capName (sRef_getAliasKind (sr)),
                                          uentry_getName (ce),
                                          cstring_makeLiteral (sRef_isKeep (sr) 
                                                               ? "transferred" : "released"),
                                          cstring_makeLiteral (isReturn 
                                                               ? "return" : "scope exit")),
                                         g_currentloc))
                                      {
                                        sRef_showAliasInfo (sr);
                                      }
                                  }
                              }
                          }
                      }
                  else
                    {
                      ;
                    }
                }
              else if (mustDefine && uentry_isOut (ce))
                {
                  if (!ynm_toBoolStrict (sRef_isReadable (sr)))
                    {
                      voptgenerror 
                        (FLG_MUSTDEFINE,
                         message ("Out storage %q not defined before %q",
                                  uentry_getName (ce),
                                  cstring_makeLiteral 
                                  (isReturn ? "return" : "scope exit")),
                         g_currentloc);
                      
                      /* uentry_showWhereDeclared (ce); */
                    }
                }
              else
                {
                  ; 
                }
              
              /*
              ** also check state is okay
              */

              if (usymtab_lexicalLevel () > functionScope
                  && uentry_isVariable (ce)
                  && (sRef_isLocalVar (sr)
                      && (sRef_isDependent (sr) || sRef_isLocalState (sr))))
                {
                  sRefSet ab = usymtab_aliasedBy (sr);

                  /* should do something more efficient here */

                  if (sRefSet_isEmpty (ab))
                    {
                      /* and no local ref */
                      checkLoseRef (ce);
                    }
                  else
                    {
                      ;
                    }
                  
                  sRefSet_free (ab);
                }
              else 
                {
                  ;
                }
              
              checked = sRefSet_insert (checked, sr);
            }
        }
      llassert (usymtab_isDefined (stab->env));

      if (usymtab_isBranch (stab))
        {
          stab = usymtab_dropEnv (stab);
        }
      else
        {
          stab = stab->env;
        }

      llassert (stab != usymtab_undefined);
    } while (isReturn && (stab->lexlevel >= paramsScope));

    sRefSet_free (checked);

  /*
  ** for returns:
  **      all globals are appropriately defined
  **      all parameters are appropriately defined
  **      special clauses are followed
  */

  if (isReturn || (utab->lexlevel == paramsScope))
    {
      uentry fcn = context_getHeader ();
      uentryList params = context_getParams ();
      globSet uglobs = context_getUsedGlobs ();
      globSet sglobs = context_getGlobs ();

            
      if (isReturn && context_maybeSet (FLG_GLOBALIAS))
        { 
          aliasTable_checkGlobs (utab->aliases); 
        }

      /*
      ** special clauses (defines, sets, allocates, releases) 
      */

      if (uentry_hasSpecialClauses (fcn))
        {
          specialClauses clauses = uentry_getSpecialClauses (fcn);

          specialClauses_elements (clauses, cl)
            {
              sRefTest tst = specialClause_getPostTestFunction (cl);
              sRefSet rfs = specialClause_getRefs (cl);

              
              sRefSet_elements (rfs, el)
                {
                  sRef base = sRef_getRootBase (el);

                  if (sRef_isResult (base))
                    {
                      ; 
                    }
                  else if (sRef_isParam (base))
                    {
                      sRef sr = sRef_updateSref (base);

                      sr = sRef_fixBase (el, sr);

                      
                      if (tst != NULL && !tst (sr))
                        {
                          if (optgenerror 
                              (specialClause_postErrorCode (cl),
                               message ("%s storage %qcorresponds to "
                                        "storage listed in %q clause",
                                        specialClause_postErrorString (cl, sr),
                                        sRef_unparseOpt (sr),
                                        specialClause_unparseKind (cl)),
                               g_currentloc))
                            {
                              sRefShower ss = specialClause_getPostTestShower (cl);

                              if (ss != NULL)
                                {
                                  ss (sr);
                                }
                            }
                          
                                                }
                    }
                  else
                    {
                      if (sRef_isMeaningful (el))
                        {
                          BADBRANCH;
                        }
                    }
                } end_sRefSet_elements ;

            } end_specialClauses_elements ;
        }


      /*
      ** check parameters on return
      */

      uentryList_elements (params, arg)
        {
          if (!uentry_isElipsisMarker (arg))
            {
              ctype rt = ctype_realType (uentry_getType (arg));

              if (ctype_isMutable (rt) || ctype_isSU (rt))
                {
                  uentry param = usymtab_lookupQuiet (utab, uentry_rawName (arg));
                  checkParamReturn (param);
                }
            }
        } end_uentryList_elements;
      
      globSet_allElements (sglobs, el)
        {
          uentry current = sRef_getUentry (el);

          if (uentry_isVariable (current) && !uentry_isRealFunction (current))
            {
              checkGlobalReturn (current, el);
            }
        } end_globSet_allElements;

      globSet_allElements (uglobs, el)
        {
          if (!globSet_member (sglobs, el))
            {
              uentry current = sRef_getUentry (el);
              
                      
              if (uentry_isVariable (current)
                  && !uentry_isRealFunction (current))
                {
                  checkGlobalReturn (current, sRef_undefined);
                }
            }
        } end_globSet_allElements;
    }
  
  }

void
usymtab_quietExitScope (fileloc loc) 
   /*@globals utab, globtab, filetab; @*/ 
   /*@modifies utab@*/
{
  usymtab t = utab->env;

  if (utab->reftable != NULL)
    {
      int i;

      for (i = 0; i < utab->nentries; i++)
        {
          uentry current = utab->entries[i];      
          uentry old = usymtab_lookupAux (t, uentry_rawName (current));

          uentry_mergeState (old, current, loc, FALSE, FALSE, FALSE, NOCLAUSE);
        }
    }

  llassert (t != NULL);

  if (t->lexlevel > paramsScope)
    {
      t->guards = guardSet_levelUnion (t->guards, utab->guards, t->lexlevel);
      t->aliases = aliasTable_levelUnionSeq (t->aliases, utab->aliases, 
                                             t->lexlevel);
      utab->aliases = aliasTable_undefined;
    }

  t->mustBreak = utab->mustBreak;
  t->exitCode = utab->exitCode;

  usymtab_freeLevel (utab);

  utab = t;
}

/*
** Exit a scope with no checking, lose alias states.
** (When should this be used?)
*/

void usymtab_quietPlainExitScope (void)
     /*@globals utab, globtab, filetab@*/
     /*@modifies utab@*/
{
  usymtab t = utab->env;

  llassert (t != NULL);
  llassert (NOALIAS (utab->aliases, t->aliases));
  usymtab_freeLevel (utab);
  utab = t;
}

void usymtab_exitScope (exprNode expr)
  /*@globals utab, filetab, globtab@*/
  /*@modifies utab, globtab@*/
{
  usymtab ctab = usymtab_undefined;
  usymtab lctab = usymtab_undefined;
  bool mustReturn = exprNode_mustEscape (expr);
  
  if (utab->kind == US_CBRANCH)
    {
      /*
      ** save the case branches, remove the first non-cbranch
      */

      ctab = utab;

      while (utab->kind == US_CBRANCH) 
        {
          lctab = utab;
          utab = utab->env;
          llassert (utab != GLOBAL_ENV);
        }
    }
  
  llassertprint (utab->kind != US_TBRANCH && utab->kind != US_FBRANCH
                 && utab->kind != US_CBRANCH && utab->kind != US_SWITCH,
                 ("exitScope: in branch: %s", usymtab_unparseStack()));

  /*
  ** check all variables in scope were used
  */

  /*
  ** bogus errors if this is the normal inside a switch,
  ** since cases have not been merged yet.  Should probably
  ** still check this, but I'm too lazy at the moment...
  */

  llassertfatal (utab->env != GLOBAL_ENV);

  if (utab->env->kind != US_SWITCH)
    {
      usymtab_allUsed ();
    }

  /*
  ** check aliasing: all only params are released (dead)
  **     definition: all out params are defined, all modified params 
  **                     are completely defined
  **
  ** NOTE: note for exiting paramsScope, since checkReturn should be
  ** called first.
  */

  if (!mustReturn && (usymtab_lexicalLevel () > functionScope))
    {
      /*
      ** should only call this is end of scope is reachable...
      */

      usymtab_checkFinalScope (FALSE);
    }

  if (usymtab_lexicalLevel () == paramsScope && context_inFunctionLike ())
    {
      /*
      ** leaving a function, need to fix up globals
      */

      uentryList params = context_getParams ();
      globSet    globs = context_getUsedGlobs ();

                  
      uentryList_elements (params, ue)
        {
          uentry_fixupSref (ue);
        } end_uentryList_elements;

      clearFunctionTypes ();

      
      globSet_allElements (globs, el)
        {
          if (sRef_isCvar (el))
            {
              uentry current;
              int index = sRef_getScopeIndex (el);
              
              if (sRef_isFileStatic (el))
                {
                  llassert (usymtab_isDefined (filetab));
                  current = usymtab_fetchIndex (filetab, index);
                }
              else
                {
                  current = usymtab_fetchIndex (globtab, index);
                }
              
              if (uentry_isVariable (current))
                {
                  uentry_fixupSref (current);
                }
              else
                {
                  sRef_clearDerived (uentry_getSref (current));
                }
            }
        } end_globSet_allElements;
    }
  
  usymtab_quietExitScope (exprNode_loc (expr));
  
  if (lctab != usymtab_undefined)
    {
      /*@i@*/ lctab->env = utab;  
      /*@i@*/ utab = ctab;
    /*@-branchstate@*/ } /*@=branchstate@*/
/*@-globstate@*/
}
/*@=globstate@*/

/*
** yikes!  don't let the '170 kids see this one...
*/

int
uentry_directParamNo (uentry ue)
{
  if (uentry_isVar (ue))
    {
      sRef sr = uentry_getSref (ue);

      if (sRef_lexLevel (sr) == functionScope)
        {
          /*@access sRef@*/ /*@-null@*/
          int index = sr->info->cvar->index;
          /*@noaccess sRef@*/ /*@=null@*/

          if (index < uentryList_size (context_getParams ()))
            {
              return index;
            }
        }
    }
  return -1;
}

/*@dependent@*/ /*@exposed@*/ uentry
  usymtab_getParam (int paramno)
  /*@globals utab@*/
{
  /*
  ** requires in a function context (checked)
  **
  ** depends on no nested functions --- the function
  ** parameters are ALWAYS one scope inside the global scope
  ** and entered in order!
  */
  usymtab s = utab;

  if (!context_inFunctionLike ())
    llfatalbug (message ("usymtab_getParam: not in function context: %q", 
                         context_unparse ()));

  while (s->lexlevel > paramsScope) 
    {
      s = s->env;
    }

  llassert (usymtab_isDefined (s));

  if (paramno >= s->nentries)
    {
      /*  
      ** Parse errors lead to this. 
      */

      uentry err = uentry_makeVariableLoc (cstring_makeLiteralTemp ("<error>"),
                                           ctype_unknown);
      
      uentry_markOwned (err);
      return (err);
    }

  return (s->entries[paramno]);
}

static /*@dependent@*/ /*@exposed@*/ uentry 
usymtab_getRefTab (/*@notnull@*/ usymtab u, int level, usymId index)
{
  uentry ue;

  
  ue = usymtab_getRefNoisy (u, level, index);

  
  if (uentry_isUndefined (ue))
    {
      llbug (message ("usymtab_getRef: out of range: %d. level = %d",
                    index, level));
    }

  
  return ue;
}

static /*@dependent@*/ /*@exposed@*/ usymtab 
  usymtab_dropEnv (/*@notnull@*/ usymtab s)
{
  if (s->kind == US_CBRANCH)
    {
      usymtab t = s;

      do 
        {
          t = s;
          s = s->env;
          llassert (s != GLOBAL_ENV);
        } while (s->kind == US_CBRANCH); 
      /* drop all cases (except in nested scopes */ 

      s = t;
      llassert (s != GLOBAL_ENV);
    }

  if (s->kind == US_FBRANCH)
    {
      s = s->env; /* skip the true branch */
      llassert (usymtab_isDefined (s));
      llassert (s->kind == US_TBRANCH);
    }

  llassert (s != GLOBAL_ENV);
  s = s->env;

  return s;
}

/*@dependent@*/ /*@exposed@*/ uentry
  usymtab_getRefQuiet (int level, usymId index)
  /*@globals utab@*/
{
  usymtab s = utab;
  
  
  llassert (s != NULL);
  llassert (index >= 0);

  if (level > s->lexlevel)
    {
            
      return uentry_undefined;
    }

  llassertprint (level <= s->lexlevel, ("level: %d / lexlevel: %d", 
                                        level, s->lexlevel)); 

  while (s->lexlevel > level)
    {
      if (usymtab_isBranch (s))
        {
          int eindex = refTable_lookup (s, level, index);

          if (eindex != NOT_FOUND)
            {
              return (s->entries[eindex]);
            }
        }

      s = usymtab_dropEnv (s);
    }

  while (usymtab_isBranch (s) && s->lexlevel == level)
    {
      int eindex = refTable_lookup (s, level, index);
      
      if (eindex != NOT_FOUND)
        {
          return (s->entries[eindex]);
        }

      s = usymtab_dropEnv (s);
    }
 
  if (index >= s->nentries)
    {
      return uentry_undefined;
    }

  llassert (!uentry_isUndefined (s->entries[index]));

  return s->entries[index];
}

static /*@dependent@*/ /*@exposed@*/ uentry
usymtab_getRefNoisy (/*@notnull@*/ usymtab s, int level, usymId index)
{
  usymtab otab = s;
  uentry ue = uentry_undefined;

  
  llassert (index >= 0);

  
  while (s->lexlevel > level)
    {
      
      if (usymtab_isBranch (s))
        {
          int eindex = refTable_lookup (s, level, index);

          if (eindex != NOT_FOUND)
            {
              ue = s->entries[eindex];

              if (s != otab)
                {
                  while (!usymtab_isBranch (otab))
                    {
                      otab = usymtab_dropEnv (otab);
                      llassert (otab != GLOBAL_ENV);
                    }
                
                  if (refTable_lookup (otab, level, index) == NOT_FOUND)
                    {
                      ue = usymtab_addRefEntry (otab, uentry_rawName (ue));
                    }
                  else
                    {
                      ;
                    }
                }
              
              return ue;
            }
        }

      s = usymtab_dropEnv (s);
    }

  llassert (usymtab_isDefined (s));

  while (usymtab_isBranch (s) && s->lexlevel == level)
    {
      int eindex = refTable_lookup (s, level, index);

      
      if (eindex != NOT_FOUND)
        {
          ue = s->entries[eindex];
          
          if (s != otab)
            {
              while (!usymtab_isBranch (otab))
                {
                  otab = usymtab_dropEnv (otab);
                  llassert (otab != GLOBAL_ENV);
                }

              ue = usymtab_addRefEntry (otab, uentry_rawName (ue));
            }
          else
            {
              ;
            } 

          return ue;
        }

      s = usymtab_dropEnv (s);
          }

  if (s->lexlevel == level && (index < s->nentries))
    {
      ue = s->entries[index];
      
      if (uentry_isValid (ue))
        {
          if (s != otab)
            {
              while (!usymtab_isBranch (otab))
                {
                  otab = usymtab_dropEnv (otab);
                  
                  if (otab == GLOBAL_ENV)
                    {
                      return ue;
                    }
                }
              
              ue = usymtab_addRefEntry (otab, uentry_rawName (ue));
            }
          else
            {
                    }
        }

      return ue;
    }

  
  if (index >= s->nentries)
    {
      return uentry_undefined;
    }

  llassert (!uentry_isUndefined (s->entries[index]));

  return s->entries[index];
}

/*
** looking up entries
**
** If entry is inside a branch, then copy it, and put it into 
** the branch table.
*/

static
int refTable_lookup (/*@notnull@*/ usymtab ut, int level, int index)
{
  refTable rt = ut->reftable;
  int i;

  llassert (rt != NULL);

  
  for (i = 0; i < ut->nentries; i++)
    {
      if (rt[i]->level == level && rt[i]->index == index)
        {
                  return i;
        }
    }

    return NOT_FOUND;
}
  
static
/*@only@*/ refentry refentry_create (int level, int index)
{
  refentry r = (refentry) dmalloc (sizeof (*r));

  r->level = level;
  r->index = index;

  return r;
}

static /*@dependent@*/ /*@exposed@*/ uentry
usymtab_addRefEntry (/*@notnull@*/ usymtab s, cstring k)
{
  int eindex;
  usymtab ut = s;

  llassert (ut->reftable != NULL);

  while (s != GLOBAL_ENV)
    {
      eindex = usymtab_getIndex (s, k);
      
      if (eindex != NOT_FOUND)
        {
          uentry current = s->entries[eindex];

          if (uentry_isVar (current) && !ctype_isFunction (uentry_getType (current)))
            {
              uentry ue;

              DPRINTF (("Here: copying %s", uentry_unparseFull (current)));

              ue = uentry_copy (current);

              DPRINTF (("Here: copying %s", uentry_unparseFull (ue)));

              usymtab_addEntryQuiet (ut, ue);

              if (s->reftable != NULL)
                {
                  refentry ref = s->reftable[eindex];

                  
                  ut->reftable[ut->nentries - 1] 
                    = refentry_create (ref->level, ref->index);
                }
              else
                {
                  ut->reftable[ut->nentries - 1] 
                    = refentry_create (s->lexlevel, eindex);
                }
              
              return (ue);
            }
          else
            {
              return (current);
            }
        }

      s = usymtab_dropEnv (s);
    }

  return uentry_undefined;
}

static uentry usymtab_lookupAux (usymtab s, cstring k)
{
  DPRINTF (("Lookup: %s", k));

  while (s != GLOBAL_ENV)
    {
      int eindex = usymtab_getIndex (s, k);

      if (eindex != NOT_FOUND)
        {
          uentry ret = s->entries[eindex];
          
          DPRINTF (("Found: %s", uentry_unparseFull (ret)));
          return (ret);
        }

      if (s->kind == US_TBRANCH || s->kind == US_FBRANCH 
          || s->kind == US_CBRANCH)
        {
          uentry ret = usymtab_addRefEntry (s, k);
          DPRINTF (("Ref entry: %s", uentry_unparseFull (ret)));
          return ret;
        }
      
      s = s->env;
    }
  
  return uentry_undefined;
}

static /*@dependent@*/ /*@exposed@*/ uentry
usymtab_lookupQuiet (usymtab s, cstring k)
{
  int eindex;

  while (s != GLOBAL_ENV)
    {
      eindex = usymtab_getIndex (s, k);
      
      if (eindex != NOT_FOUND)
        {
          uentry ret = s->entries[eindex];
          return (ret);
        }
      
      s = s->env;
    }

  return uentry_undefined;
}

/*@dependent@*/ /*@observer@*/ uentry
  usymtab_lookupSafe (cstring k)
  /*@globals utab@*/
{
  DPRINTF (("Lookup safe: %s", k));
  return (usymtab_lookupAux (utab, k));
}

uentry
  usymtab_lookupExpose (cstring k)
  /*@globals utab@*/
{
  uentry ce = usymtab_lookupAux (utab, k);

  if (uentry_isUndefined (ce))
    {
      llfatalbug (message ("usymtab_lookup: not found: *%s*", k));
    }

  if (uentry_isPriv (ce))
    {
      llfatalbug (message ("usymtab_lookup: private: *%s*", k));
    }

  return ce;
}

uentry usymtab_lookupExposeGlob (cstring k)
{
  return (usymtab_lookupGlobSafe (k));
}

uentry usymtab_lookupGlob (cstring k)
  /*@globals globtab@*/
{
  uentry ce = usymtab_lookupAux (globtab, k);

  if (uentry_isUndefined (ce))
    llfatalbug (message ("usymtab_lookup: not found: %s", k));

  if (uentry_isPriv (ce))
    llfatalbug (message ("usymtab_lookup: private: %s", k));

  return ce;
}

/*@observer@*/ uentry
  usymtab_lookupGlobSafe (cstring k)
  /*@globals globtab@*/
{
  uentry ce = usymtab_lookupAux (globtab, k);

  return ce;
}

uentry usymtab_lookupEither (cstring k)
   /*@globals utab@*/
{
  uentry ce = usymtab_lookupSafe (k);

  if (uentry_isUndefined (ce))
    llfatalerror (message ("usymtab_lookup: not found: %s", k));

  return ce;
}

# ifndef NOLCL
ctype
usymtab_lookupType (cstring k)
   /*@globals globtab@*/
{
  usymId uid = usymtab_getTypeId (k);

  if (uid == USYMIDINVALID)
    {
      llcontbug (message ("usymtab_lookupType: not found: %s", k));
      return ctype_unknown;
    }
  
  return (uentry_getRealType (usymtab_getTypeEntry (uid)));
}
# endif

ctype
usymtab_lookupAbstractType (cstring k) /*@globals globtab@*/
{
  usymId uid = usymtab_getTypeId (k);

  if (uid == USYMIDINVALID)
    {
      llcontbug (message ("usymtab_lookupType: not found: %s", k));
      return ctype_unknown; 
    }
  
  return (uentry_getAbstractType (usymtab_getTypeEntry (uid)));
}
  
/*
** if there is an unnamed lcl-specified struct tag matching
** the uentryList, return its datatype.  Otherwise, returns
** ctype_undefined.
*/

ctype
usymtab_structFieldsType (uentryList f)
   /*@globals globtab@*/
{
  return (usymtab_suFieldsType (f, TRUE));
}

ctype
usymtab_unionFieldsType (uentryList f)
   /*@globals globtab@*/
{
  return (usymtab_suFieldsType (f, FALSE));
}

static ctype
usymtab_suFieldsType (uentryList f, bool isStruct)
  /*@globals globtab@*/
{
  int i;

  if (fileloc_isSpec (g_currentloc)) return (ctype_undefined);

  for (i = 0; i < globtab->nentries; i++)
    {
      uentry current = globtab->entries[i];

      if ((isStruct 
           ? uentry_isStructTag (current) : uentry_isUnionTag (current)))
        {
          if (isFakeTag (uentry_rawName (current)))
            {
              ctype ct = uentry_getType (current);

              if ((isStruct ? ctype_isStruct (ct) : ctype_isUnion (ct))
                  && (uentryList_matchFields (f, ctype_getFields (ct))))
                {
                                  return uentry_getAbstractType (current);
                }
            }
        }
    }
  
    return ctype_undefined;
}

ctype
  usymtab_enumEnumNameListType (enumNameList f)
  /*@globals globtab@*/
{
  int i;

  for (i = 0; i < globtab->nentries; i++)
    {
      uentry current = globtab->entries[i];

      if (uentry_isEnumTag (current))
        {
          if (isFakeTag (uentry_rawName (current)))
            {
              ctype ct = uentry_getType (current);

              if (ctype_isEnum (ct) && (enumNameList_match (f, ctype_elist (ct))))
                {
                  return uentry_getType (current);
                }
            }
        }
    }
  
  return ctype_undefined;
}

bool
usymtab_exists (cstring k)
   /*@globals utab@*/
{
  uentry ce = usymtab_lookupSafe (k);

  return (!(uentry_isUndefined (ce)) && !(uentry_isPriv (ce)));
}

bool
usymtab_existsReal (cstring k)
   /*@globals utab@*/
{
  uentry ce = usymtab_lookupSafe (k);

  return (!(uentry_isUndefined (ce)) 
          && !(uentry_isPriv (ce))
          && !(uentry_isExpandedMacro (ce)));
}

bool
  usymtab_existsGlob (cstring k)
  /*@globals globtab@*/
{
  uentry ce = usymtab_lookupAux (globtab, k);

  return (!(uentry_isUndefined (ce)) && !(uentry_isPriv (ce)));
}

# ifndef NOLCL
bool
usymtab_existsEither (cstring k)
  /*@globals utab@*/
{
  uentry ce = usymtab_lookupAux (utab, k);
  
  return (uentry_isValid (ce));
}

bool
  usymtab_existsGlobEither (cstring k)
  /*@globals globtab@*/
{
  uentry ce = usymtab_lookupAux (globtab, k);
  
  return (uentry_isValid (ce));
}
# endif

bool
usymtab_existsType (cstring k)
  /*@globals globtab@*/
{
  uentry ce = usymtab_lookupAux (globtab, k);

  return (!(uentry_isUndefined (ce)) && !(uentry_isPriv (ce)) && uentry_isDatatype (ce));
}

bool
usymtab_existsTypeEither (cstring k)
  /*@globals globtab@*/
{
  uentry ce = usymtab_lookupAux (globtab, k);

    return (uentry_isValid (ce) && uentry_isDatatype (ce));
}

bool
usymtab_existsStructTag (cstring k) /*@globals globtab@*/
{
  cstring sname = makeStruct (k);
  uentry ce = usymtab_lookupAux (globtab, sname);

  cstring_free (sname);

  
  return (!(uentry_isUndefined (ce)) && !(uentry_isPriv (ce)));
}

bool
usymtab_existsUnionTag (cstring k) /*@globals globtab@*/
{
  cstring uname = makeUnion (k);
  uentry ce = usymtab_lookupAux (globtab, uname);

  cstring_free (uname);

  return (!(uentry_isUndefined (ce)) && !(uentry_isPriv (ce)));
}

bool
usymtab_existsEnumTag (cstring k) /*@globals globtab@*/
{
  cstring ename = makeEnum (k);
  uentry ce = usymtab_lookupAux (globtab, ename);

  cstring_free (ename);
  return (!(uentry_isUndefined (ce)) && !(uentry_isPriv (ce)));
}

# ifndef NOLCL
bool usymtab_existsVar (cstring k)
   /*@globals utab@*/
{
  uentry ce = usymtab_lookupSafe (k);

  return (!(uentry_isUndefined (ce)) && !(uentry_isPriv (ce)) && (uentry_isVar (ce)));
}
# endif

/*
** destructors
*/

static void
refTable_free (/*@only@*/ /*@null@*/ refTable x, int nentries)
{
  if (x != NULL)
    {
      int i;

      for (i = 0; i < nentries; i++)
        {
          sfree (x[i]);
        }
      
      sfree (x);
    }
}
  
static void
usymtab_freeLevel (/*@notnull@*/ /*@only@*/ usymtab u)
  /*@globals globtab, utab, filetab@*/
{
  int i;

  aliasTable_free (u->aliases);

  refTable_free (u->reftable, u->nentries);

  if (u == filetab || u == globtab)
    {
      for (i = 0; i < u->nentries; i++)
        {
          uentry_freeComplete (u->entries[i]);
        }
    }
  else
    {
      for (i = 0; i < u->nentries; i++)
        {
          uentry_free (u->entries[i]);
        }
    }

  guardSet_free (u->guards);
  sfree (u->entries);

  if (u != globtab 
      && u != utab
      && u != filetab)
    {
      llassert (u->htable == NULL);
      sfree (u);
    }

/*@-mustfree@*/
} /*@=mustfree@*/

static void
usymtab_freeAux (/*@only@*/ usymtab u)
   /*@globals globtab, utab, filetab@*/
   /*@modifies u@*/
{
  while (u != GLOBAL_ENV)
    {
      usymtab t = u->env;
      usymtab_freeLevel (u);
      u = t;
      /*@-branchstate@*/ 
    } 
  /*@=branchstate@*/
}

void usymtab_free () 
  /*@globals killed utab, globtab, filetab@*/ 
  /*@modifies utab@*/
{
  dbgfree = TRUE;
  usymtab_freeAux (utab);
}

static int usymtab_lexicalLevel (void) /*@globals utab@*/
{
  return (utab->lexlevel);
}

bool usymtab_inGlobalScope () /*@globals utab, globtab@*/
{
  return (utab == globtab);
}

bool usymtab_inFileScope () /*@globals utab@*/
{
  return (utab->lexlevel == fileScope);
}

bool usymtab_inFunctionScope () /*@globals utab@*/
{
  return (utab->lexlevel == functionScope);
}

# ifndef NOLCL
void
usymtab_replaceEntry (uentry s)
  /*@globals utab, globtab@*/
  /*@modifies utab, s@*/
{
  usymtab_replaceEntryAux (utab, s);
}
# endif

bool
usymtab_matchForwardStruct (usymId u1, usymId u2)
   /*@globals globtab@*/
{
  uentry ue1 = usymtab_getTypeEntry (u1);
  uentry ue2 = usymtab_getTypeEntry (u2);

  if (uentry_isAnyTag (ue2))
    {
      ctype reptype = uentry_getType (ue1);
      
      if (ctype_isPointer (reptype))
        {
          ctype repbase = ctype_getBaseType (reptype);
  
          if (ctype_isUA (repbase))
            {
              typeId rtuid = ctype_typeId (repbase);

              if (u2 == rtuid) return TRUE;
              
              if (usymId_isValid (rtuid))
                {
                  reptype = uentry_getType (usymtab_getTypeEntry (rtuid));
                  
                  return (ctype_isUA (reptype) && (u2 == (ctype_typeId (reptype))));
                }
            }
        }
    }
  
  return FALSE;
}

void usymtab_addGuards (guardSet guards)
  /*@modifies utab@*/
{
  utab->guards = guardSet_union (utab->guards, guards);
  }

static bool usymtab_isGuardedAux (sRef s)
  /*@globals utab@*/
{
  usymtab tab = utab;
  sRef base = sRef_getRootBase (s);
  int lowlevel = paramsScope;
  int baselevel = sRef_lexLevel (base);

  if (sRef_isCvar (base))
    {
      lowlevel = baselevel;
      if (lowlevel < paramsScope) lowlevel = paramsScope;
    }
  
  while (tab->lexlevel >= lowlevel)
    {
      if (guardSet_isGuarded (tab->guards, s))
        {
          /*
          if (!sRef_definitelyNull (s))
            {
              sRef_setNotNull (s, fileloc_undefined);
            }
            */
          return TRUE;
        }

      tab = usymtab_dropEnv (tab);
    }
  
  return FALSE;
}

void usymtab_unguard (sRef s) /*@modifies utab@*/
{
  usymtab tab = utab;
  sRef base = sRef_getRootBase (s);
  int lowlevel = paramsScope;
  int baselevel = sRef_lexLevel (base);
  
  if (sRef_isCvar (base))
    {
      lowlevel = baselevel;
      if (lowlevel < paramsScope) lowlevel = paramsScope;
    }

  while (tab->lexlevel >= lowlevel)
    {
      if (guardSet_isGuarded (tab->guards, s))
        {
          guardSet_delete (tab->guards, s);
        }
      
      tab = usymtab_dropEnv (tab);
    }
}

bool usymtab_isGuarded (sRef s)
{
  
  return (sRef_aliasCompleteSimplePred (usymtab_isGuardedAux, s));
}

bool usymtab_isProbableNull (sRef s)
{
  return (sRef_aliasCheckSimplePred (usymtab_isProbableNullAux, s));
}

bool usymtab_isProbableDeepNull (sRef s)
{
  return (sRef_deepPred (usymtab_isProbableNull, s));
}

static bool usymtab_isProbableNullAux (sRef s)
  /*@globals utab@*/
{
  usymtab tab = utab;
  sRef base = sRef_getRootBase (s);
  int  lowlevel = paramsScope;
  
  if (sRef_isCvar (base))
    {
      lowlevel = sRef_lexLevel (base);
      if (lowlevel < paramsScope) lowlevel = paramsScope;
    }
  
  while (tab->lexlevel >= lowlevel)
    {
      if (guardSet_isProbableNull (tab->guards, s))
        {
          return TRUE;
        }
      
      while (tab->kind == US_CBRANCH) 
        {
          tab = tab->env;
        }

      llassert (usymtab_isDefined (tab));

      if (tab->kind == US_FBRANCH)
        {
          tab = tab->env;
          llassert (tab->kind == US_TBRANCH);
        }
      
      tab = tab->env;
    }

  return FALSE;
}

void
usymtab_printGuards ()
  /*@globals utab, globtab@*/
{
  usymtab ttab = utab;

  while (ttab != globtab)
    {
      llmsg (message ("Guards [%d]: %q", ttab->lexlevel,
                      guardSet_unparse (ttab->guards)));
      ttab = ttab->env;
    }
}

void
usymtab_displayAllUses ()
  /*@globals utab, globtab@*/
{
  usymtab copy;

  /* only in top scope */
  llassert (utab == globtab);

  /* need a copy, so order is not messed up by sort! */  
  copy = usymtab_shallowCopy (globtab); 
  
  qsort (copy->entries, (size_t)copy->nentries, 
         sizeof (*copy->entries), (int (*)(const void *, const void *)) uentry_xcompareuses);

  usymtab_entries (copy, ue)
    {
      if (uentry_isValid (ue))
        {
          filelocList uses = uentry_getUses (ue);
          int size = filelocList_realSize (uses);

          if (fileloc_isDefined (uentry_whereDefined (ue)) 
              && !fileloc_isLib (uentry_whereDefined (ue))
              && (size > 0))
            {
              llmsg (message ("%q (%q), %d use%p:\n   %q", 
                              uentry_getName (ue),
                              fileloc_unparse (uentry_whereDefined (ue)),
                              size, filelocList_unparseUses (uses)));
            }
        }
    } end_usymtab_entries;
  
  usymtab_shallowFree (copy);
}

static /*@dependent@*/ /*@exposed@*/ usymtab
usymtab_getFileTab ()
  /*@globals filetab@*/
{
  llassert (filetab != NULL);

  return filetab;
}

/*@only@*/ cstring
usymtab_unparseStack ()
  /*@globals utab@*/
{
  return (usymtab_unparseStackTab (utab));
}
 
static /*@only@*/ cstring
usymtab_unparseStackTab (usymtab t)
{
  bool firstOne = TRUE;
  cstring ret = cstring_makeLiteral ("[");

  while (t != GLOBAL_ENV)
    {
      if (firstOne)
        {
          ret = message ("%q %q", ret, usymtab_typeName (t));
          firstOne = FALSE;
        }
      else
        {
          ret = message ("%q, %q", ret, usymtab_typeName (t));
        }
      t = t->env;
    }

  ret = message ("%q ]", ret);
  return ret;
}

static /*@only@*/ cstring
usymtab_typeName (/*@notnull@*/ usymtab t)
{
  switch (t->kind)
    {
    case US_GLOBAL:  return cstring_makeLiteral ("global");
    case US_NORMAL:  return cstring_makeLiteral ("normal");
    case US_TBRANCH: return cstring_makeLiteral ("true");
    case US_FBRANCH: return cstring_makeLiteral ("false");
    case US_CBRANCH: return cstring_makeLiteral ("case");
    case US_SWITCH:  return cstring_makeLiteral ("switch");
    }
  
  BADEXIT;
}

void usymtab_addMustAlias (sRef s, sRef al)
  /*@modifies utab@*/
{
  if (sRef_isMeaningful (s) && sRef_isMeaningful (al)
      && !(sRef_isConst (s) || sRef_isConst (al))
      && !(sRef_isAddress (al) && sRef_isDirectParam (sRef_getBase (al)))
      && !(sRef_similar (s, al)))
    {
      utab->aliases = aliasTable_addMustAlias (utab->aliases, s, al); 
      DPRINTF (("Must alias: %s", aliasTable_unparse (utab->aliases)));

      /*
      ** for local variable, aliasing is symmetric 
      */
      
      if (sRef_isLocalVar (s) && sRef_isLocalVar (al))
        {
          utab->aliases = aliasTable_addMustAlias (utab->aliases, al, s); 
        }
    }
  else
    {
      ;
    }
}

/*
** Same as usymtab_addMustAlias, except does not check sRef_isSimilar.
*/

void usymtab_addForceMustAlias (sRef s, sRef al)
  /*@modifies utab@*/
{
  if (sRef_isMeaningful (s) 
      && sRef_isMeaningful (al)
      && !(sRef_isConst (s) || sRef_isConst (al))
      && !(sRef_isAddress (al) && sRef_isDirectParam (sRef_getBase (al))))
    {
      utab->aliases = aliasTable_addMustAlias (utab->aliases, s, al); 
      DPRINTF (("Must alias: %s", aliasTable_unparse (utab->aliases)));

      /*
      ** for local variable, aliasing is symmetric 
      */
      
      if (sRef_isLocalVar (s) && sRef_isLocalVar (al))
        {
          utab->aliases = aliasTable_addMustAlias (utab->aliases, al, s); 
        }
    }
  else
    {
      ;
    }
}

void usymtab_clearAlias (sRef s)
  /*@modifies utab, s@*/
{
  
  aliasTable_clearAliases (utab->aliases, s); 
}

sRefSet usymtab_allAliases (sRef s)
   /*@globals utab@*/  
{
  if (sRef_isMeaningful (s))
    {
      sRefSet ret;

            
      ret = sRefSet_unionFree (aliasTable_aliasedBy (utab->aliases, s),
                               aliasTable_canAlias (utab->aliases, s));
            return (ret);
    }
  else
    {
      return sRefSet_undefined;
    }
}

/*@only@*/ sRefSet usymtab_canAlias (sRef s)
  /*@globals utab@*/
{
  if (sRef_isMeaningful (s))
    {
      sRefSet res = aliasTable_canAlias (utab->aliases, s);

      return res;
    }

  return sRefSet_undefined;
}

/*@only@*/ sRefSet usymtab_aliasedBy (sRef s)
  /*@globals utab@*/
{
  return (aliasTable_aliasedBy (utab->aliases, s));
}

/*@only@*/ cstring usymtab_unparseAliases ()
  /*@globals utab@*/
{
  return (aliasTable_unparse (utab->aliases));
}

/*
** Debugging routines:
**    okay to leak storage here, only for debugging 
*/

/*@-mustfree@*/ 

void
usymtab_printOut (void)
  /*@globals utab@*/
{
  int i;
  usymtab s = utab;
  int depth = 0;
  char *ind = mstring_copy ("               ");

  fprintf (g_msgstream, "<<< [symbol table] >>>\n");
  
  while (s != GLOBAL_ENV && s->env != GLOBAL_ENV)
    {
      cstring tname = usymtab_typeName (s);

      if (depth < 5)
        {
          ind[depth * 3 + 1] = '\0';
        }
     
      fprintf (g_msgstream, "level: %d (%s)\n", s->lexlevel,
               cstring_toCharsSafe (tname));

      cstring_free (tname);

      for (i = 0; i < s->nentries; i++)
        {
          cstring us = uentry_unparseFull (s->entries[i]);
          fprintf (g_msgstream, "%s\n", cstring_toCharsSafe (us));
          cstring_free (us);
        }
      
      if (s->reftable != NULL && s->nentries > 0)
        {
          fprintf (g_msgstream, "\t<< Ref table >>\n");

          for (i = 0; i < s->nentries; i++)
            {
              fprintf (g_msgstream, "\t%s %3d: %d, %d\n", ind, i, 
                       s->reftable[i]->level,
                       s->reftable[i]->index);
            }
        }

      ind[depth * 3 + 1] = ' ';
      depth++;
      s = s->env;
    }
  fprintf (g_msgstream, "<<< end usymtab >>>\n");
  mstring_free (ind);
  return;
}

void
usymtab_printTypes ()
  /*@globals globtab@*/
{
  usymtab_printAllAux (globtab);
}

void 
usymtab_printAll (void)
  /*@globals utab@*/
{
  usymtab_printAllAux (utab);
}

static void
usymtab_printAllAux (usymtab s)
   /*@modifies g_msgstream@*/
{
  int i;
  int depth = 0;
  char *ind = mstring_copy ("               ");

  printf ("[[[ usymtab ]]]");

  while (s != GLOBAL_ENV)
    {
      if (depth < 5)
        ind[depth * 3 + 1] = '\0';
      
      if (s->env == GLOBAL_ENV)
        {
          int looplow;

          printf ("level: %d / break: %s / exit: %s\n", s->lexlevel,
                  cstring_toCharsSafe (bool_unparse (s->mustBreak)), 
                  cstring_toCharsSafe (exitkind_unparse (s->exitCode)));

          looplow = 0;

          for (i = looplow; i < s->nentries; i++)
            {
              printf ("%s%3d. %s\n", ind, i, 
                      cstring_toCharsSafe (uentry_unparseFull (s->entries[i])));
            }
        }
      else
        {
          printf ("level: %d / break: %s / exit: %s\n", s->lexlevel,
                  cstring_toCharsSafe (bool_unparse (s->mustBreak)),
                  cstring_toCharsSafe (exitkind_unparse (s->exitCode)));

          for (i = 0; i < s->nentries; i++)
            {
              printf ("%s%3d %s\n", ind, i, 
                     cstring_toCharsSafe (uentry_unparseFull (s->entries[i])));
            }
        }
      
      ind[depth * 3 + 1] = ' ';
      depth++;
      s = s->env;
    }
  printf ("----------\n");
}

void
usymtab_printComplete ()
  /*@globals utab@*/
{
  int i;
  int depth = 0;
  char *ind = mstring_copy ("               ");
  usymtab s = utab;

  while (s != GLOBAL_ENV)
    {
      if (depth < 5)
        {
          ind[depth * 3 + 1] = '\0';
        }
      
      if (s->env == GLOBAL_ENV)
        {
          int looplow;

          printf ("level: %d\n", s->lexlevel);

          looplow = 0;

          for (i = looplow; i < s->nentries; i++)
            {
              printf ("%s%3d %s\n", ind, i, 
                      cstring_toCharsSafe (uentry_unparse (s->entries[i])));
            }
        }
      else
        {
          printf ("level: %d\n", s->lexlevel);
          for (i = 0; i < s->nentries; i++)
            {
              printf ("%s%3d %s\n", ind, i, 
                     cstring_toCharsSafe (uentry_unparse (s->entries[i])));
            }
        }
      
      ind[depth * 3 + 1] = ' ';
      depth++;
      s = s->env;
    }

  printf ("----------\n");
  mstring_free (ind);
}

static /*@only@*/ cstring /*@unused@*/ 
usymtab_unparseLocalAux (/*@notnull@*/ usymtab s)
{
  cstring c = message ("lexlevel: %d\n", s->lexlevel);
  int i;

  for (i = 0; i < s->nentries; i++)
    {
      c = message ("%q\n%q", c, uentry_unparseFull (s->entries[i]));
    }

  c = message ("%q\n=========", c);
  return (c);
}

static cstring /*@unused@*/ /*@only@*/ 
usymtab_unparseLocalList (/*@notnull@*/ usymtab s)
{
  cstring c = message ("[%d/%s/%s] ", s->lexlevel, 
                       bool_unparse (s->mustBreak), 
                       exitkind_unparse (s->exitCode));
  int i;

  for (i = 0; i < s->nentries; i++)
    {
      sRef sr = uentry_getSref (s->entries[i]);

      if (i == 0)
        {
          c = message ("%q: %q [%b]", c, uentry_getName (s->entries[i]), 
                       sRef_isStateDefined (sr));
        }
      else
        {
          c = message ("%q, %q [%b]", c, uentry_getName (s->entries[i]), 
                       sRef_isStateDefined (sr));
        }

    }

  return (c);
}

void
usymtab_printLocal (void)
  /*@globals utab@*/
{
  int i;
  usymtab s = utab;

  printf ("lexlevel: %d\n", s->lexlevel);

  for (i = 0; i < s->nentries; i++)
    {
      printf ("%s\n", cstring_toCharsSafe (uentry_unparseFull (s->entries[i])));
    }
  
  while (s->lexlevel > 1)
    {
      s = s->env;
    }

  llassert (usymtab_isDefined (s));

  printf ("Params:\n");

  for (i = 0; i < s->nentries; i++)
    {
      printf ("%d: %s\n", i, 
              cstring_toCharsSafe (uentry_unparseFull (s->entries[i])));
    }
}
/*@=mustfree@*/

static bool checkDistinctExternalName (uentry e)
  /*@globals globtab@*/
  /*@modifies *g_msgstream@*/
{
  int checklen = context_getValue (FLG_EXTERNALNAMELEN);
  bool ignorecase = context_getFlag (FLG_EXTERNALNAMECASEINSENSITIVE);
  bool gotone = FALSE;
  bool extras = FALSE;
  bool hasError = FALSE;
  cstring name = uentry_rawName (e);
  usymtab st = globtab;

  if (checklen == 0)
    {
      ;
    }
  else
    {
      if (uentry_isAnyTag (e)) 
        {
          checklen++;  /* the tag marker doesn't count */
        }
    }

  usymtab_entries (st, oe)
    {
      if (uentry_sameObject (oe, e))
        {
          continue;
        }

      if (checklen == 0)
        {
          if (cstring_equalCaseInsensitive (uentry_rawName (oe), name))
            {
              if (gotone)
                {
                  extras = TRUE;
                  break;
                }
              
              if (optgenerror 
                  (FLG_DISTINCTEXTERNALNAMES,
                   message 
                   ("External identifier %q is not distinguishable from %q "
                    "because alphabetical case is ignored",
                    uentry_getName (e),
                    uentry_getName (oe)),
                   uentry_whereLast (e)))
                {
                  uentry_showWhereAny (oe);
                  uentry_setHasNameError (oe);
                  gotone = TRUE;
                }
            }
        }
      else
        {
          if (ignorecase)
            {
              if (cstring_equalLenCaseInsensitive (uentry_rawName (oe),
                                                   name, checklen))
                {
                  if (gotone)
                    {
                      extras = TRUE;
                      break;
                    }
                  
                  if (cstring_equalLen (uentry_rawName (oe), name, checklen))
                    {
                      if (optgenerror 
                          (FLG_DISTINCTEXTERNALNAMES,
                           /*@-sefparams@*/
                           message 
                           ("External identifier %q is not distinguishable from %q "
                            "in the first %d characters (%q)",
                            uentry_getName (e),
                            uentry_getName (oe),
                            checklen,
                            cstring_clip (uentry_getName (e), checklen)),
                           /*@=sefparams@*/
                           uentry_whereLast (e)))
                        {
                          uentry_showWhereAny (oe);
                          uentry_setHasNameError (oe);
                          gotone = TRUE;
                        }
                    }
                  else
                    {
                      if (gotone)
                        {
                          extras = TRUE;
                          break;
                        }
                      
                      if (optgenerror 
                          (FLG_DISTINCTEXTERNALNAMES,
                           message 
                           ("External identifier %q is not distinguishable from %q "
                            "in the first %d characters because alphabetical case "
                            "is ignored",
                            uentry_getName (e),
                            uentry_getName (oe),
                            checklen),
                           uentry_whereLast (e)))
                        {
                          uentry_showWhereAny (oe);
                          uentry_setHasNameError (oe);
                          gotone = TRUE;
                        }
                    }
                }
            }
          else if (cstring_equalLen (uentry_rawName (oe), name, checklen))
            {
              if (gotone)
                {
                  extras = TRUE;
                  break;
                }
              
              if (optgenerror 
                  (FLG_DISTINCTEXTERNALNAMES,
                   /*@-sefparams@*/
                   message 
                   ("External identifier %q is not distinguishable from %q "
                    "in the first %d characters (%q)",
                    uentry_getName (e),
                    uentry_getName (oe),
                    checklen,
                    cstring_clip (uentry_getName (e), checklen)),
                   /*@=sefparams@*/
                   uentry_whereLast (e)))
                {
                  uentry_showWhereAny (oe);
                  uentry_setHasNameError (oe);
                  gotone = TRUE;
                }
            }
          else
            {
              ; /* okay */
            }
        }
    } end_usymtab_entries ;

  hasError = gotone;
  
  if (extras)
    {
      llgenindentmsgnoloc
        (cstring_makeLiteral ("One or more additional "
                              "indistinguishable external "
                              "names not reported"));
    }

  return hasError;
}

static bool checkDistinctInternalName (uentry e)
  /*@globals utab@*/
  /*@modifies *g_msgstream@*/
{
  usymtab ttab = utab;
  cstring name = uentry_rawName (e);
  int numchars = context_getValue (FLG_INTERNALNAMELEN);
  bool caseinsensitive = context_getFlag (FLG_INTERNALNAMECASEINSENSITIVE);
  bool lookalike = context_getFlag (FLG_INTERNALNAMELOOKALIKE);

  if (uentry_isAnyTag (e) && (numchars != 0))
    {
      numchars++;  /* the tag marker doesn't count */
    }
  
  while (usymtab_isDefined (ttab))
    {
      usymtab_entries (ttab, oe)
        {
          if (uentry_sameObject (oe, e))
            {
              /*@innercontinue@*/ continue;
            }

          switch (cstring_genericEqual
                  (name, uentry_rawName (oe),
                   numchars, caseinsensitive, lookalike))
            {
            case CGE_DISTINCT: /* okay */
              /*@switchbreak@*/ 
              break;
            case CGE_SAME:
              if (cstring_equal (name, uentry_rawName (oe)))
                {
                  ; /* got a shadow error */
                }
              else
                {
                  if (optgenerror 
                      (FLG_DISTINCTINTERNALNAMES,
                       /*@-sefparams@*/
                       message 
                       ("Internal identifier %q is not distinguishable from %q "
                        "in the first %d characters (%q)",
                        uentry_getName (e),
                        uentry_getName (oe),
                        numchars,
                        cstring_clip (uentry_getName (e), numchars)),
                       /*@=sefparams@*/
                       uentry_whereLast (e)))
                    {
                      uentry_showWhereAny (oe);
                      uentry_setHasNameError (oe);
                      return TRUE;
                    }
                }
              /*@switchbreak@*/
              break;
            case CGE_CASE:
              if (numchars == 0 
                  || (cstring_length (name) <= numchars))
                {
                  if (optgenerror 
                      (FLG_DISTINCTINTERNALNAMES,
                       message 
                       ("Internal identifier %q is not distinguishable from %q "
                        "without case sensitivity",
                        uentry_getName (e),
                        uentry_getName (oe)),
                       uentry_whereLast (e)))
                    {
                      uentry_showWhereAny (oe);
                      uentry_setHasNameError (oe);
                      return TRUE;
                    }
                }
              else 
                {
                  if (optgenerror 
                      (FLG_DISTINCTINTERNALNAMES,
                       message 
                       ("Internal identifier %q is not distinguishable from %q "
                        "in the first %d characters without case sensitivity",
                        uentry_getName (e),
                        uentry_getName (oe),
                        numchars),
                       uentry_whereLast (e)))
                    {
                      uentry_showWhereAny (oe);
                      uentry_setHasNameError (oe);
                      return TRUE;
                    }
                }
              /*@switchbreak@*/ 
              break;
            case CGE_LOOKALIKE:
              if (numchars == 0 
                  || (cstring_length (name) <= numchars))
                {
                  if (optgenerror 
                      (FLG_DISTINCTINTERNALNAMES,
                       message 
                       ("Internal identifier %q is not distinguishable from %q "
                        "except by lookalike characters",
                        uentry_getName (e),
                        uentry_getName (oe)),
                       uentry_whereLast (e)))
                    {
                      uentry_showWhereAny (oe);
                      uentry_setHasNameError (oe);
                      return TRUE;
                    }
                }
              else 
                {
                  if (optgenerror 
                      (FLG_DISTINCTINTERNALNAMES,
                       message 
                       ("Internal identifier %q is not distinguishable from %q "
                        "in the first %d characters except by lookalike characters",
                        uentry_getName (e),
                        uentry_getName (oe),
                        numchars),
                       uentry_whereLast (e)))
                    {
                      uentry_showWhereAny (oe);
                      uentry_setHasNameError (oe);
                      return TRUE;
                    }
                }
            }
        } end_usymtab_entries ;
      
      ttab = ttab->env;
    }

  return FALSE;
}

void usymtab_checkDistinctName (uentry e, int scope)
   /*@globals utab, globtab@*/
{
  bool hasError = FALSE;
  fileloc where = uentry_whereLast (e);

  if (!fileloc_isPreproc (where)  && !fileloc_isBuiltin (where))
    {
      if (scope == globScope)
        {
          if (context_getFlag (FLG_DISTINCTEXTERNALNAMES))
            {
              hasError = checkDistinctExternalName (e);
            }
        }
      
      if (!hasError && context_getFlag (FLG_DISTINCTINTERNALNAMES))
        {
          hasError = checkDistinctInternalName (e);
        }
    }

  if (hasError)
    {
            uentry_setHasNameError (e);
    }
}